Answer:
Part 1) The number of classes must be greater than 20
Part 2) see the explanation
Part 3)
![\$68.76](https://img.qammunity.org/2020/formulas/mathematics/middle-school/yzts0iyi33odopbf1udrw7nz5ybhbfopkd.png)
Part 4)
![\$12\ per\ hour](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6wf8cxy81iizahrg0g6ferepp1h3sq95s7.png)
Part 5) The equation that can be used is
and the cost of one print is
![\$8.99](https://img.qammunity.org/2020/formulas/mathematics/middle-school/wf8jpac65t27hkab7pi95ncm3x2zdgj1pb.png)
Part 6) The number of classes must be greater than 30
Explanation:
Part 1) we know that
The linear equation in slope intercept form is equal to
![y=mx+b](https://img.qammunity.org/2020/formulas/mathematics/high-school/8nudzfk4b5l0arb9iixag2w8am6zn99zlr.png)
where
m is the slope or unit rate
b is the y-intercept or initial value
Let
y ----> the total cost
x ----> the number of classes
we have
Members
The slope is
![m=\$10\ per\ class](https://img.qammunity.org/2020/formulas/mathematics/middle-school/46hhlzb3lacq7ueerusaf39o1kbxxdl7f6.png)
The y-intercept is
![b=\$100](https://img.qammunity.org/2020/formulas/mathematics/middle-school/483kqmihzm8aj4z2c9ak4scia3ktgzfr4t.png)
so
----> equation A
Non-Members
The slope is
![m=\$15\ per\ class](https://img.qammunity.org/2020/formulas/mathematics/middle-school/p1p7ccqfdc5s3fctfgq0qj5vpjyppe3h3k.png)
so
----> equation B
To find out how many classes would a member have to take to save money compared to taking classes as a non-member, solve the following inequality
![10x+100 < 15x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/eqd02f99grjy62ai40kf56gtvik9sg4m4d.png)
Solve for x
subtract 10 x both sides
![100 < 15x-10x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/z8sw07mk5mu7lulnw784g2sbvfo3gmwosl.png)
![100 < 5x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/is9zll6b8okig4anxpuukroq13pi5fm2z3.png)
Divide by 5 both sides
![20 < x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/77ok78mw6ib5fcqnrkl44yo0ls0fehvl1b.png)
Rewrite
![x > 20](https://img.qammunity.org/2020/formulas/mathematics/middle-school/tqa91kld3bz61d9ny3rsznclzi40sva9ru.png)
therefore
The number of classes must be greater than 20
Part 2) we have
The sum of 8 and 3 times a number is 23.
Let
x ----> the number
Remember that
3 times a number is the same that multiply 3 by the number ----> 3x
so
The sum of 8 and 3 times a number is 23 is the same that
![8+3x=23](https://img.qammunity.org/2020/formulas/mathematics/middle-school/7bmlfeo0rd636nfywuqmes8it5d9mss998.png)
solve for x
subtract 8 both sides
![3x=23-8](https://img.qammunity.org/2020/formulas/mathematics/middle-school/87lefkmpfo4ahjej8qms1ao95t013m7l4s.png)
![3x=15](https://img.qammunity.org/2020/formulas/mathematics/middle-school/52lfbwca6r440c8bolrviphn51nii3n9uo.png)
Divide by 3 both sides
![x=5](https://img.qammunity.org/2020/formulas/mathematics/high-school/o5m8b661p5jd65tmflgivq8gybwcjq1o2n.png)
Part 3) we know that
The linear equation in slope intercept form is equal to
![y=mx+b](https://img.qammunity.org/2020/formulas/mathematics/high-school/8nudzfk4b5l0arb9iixag2w8am6zn99zlr.png)
where
m is the slope or unit rate
b is the y-intercept or initial value
Let
y ----> the total cost of renting a car for one day
x ----> the number of miles
we have
The slope is
![m=\$0.42\ per\ mile](https://img.qammunity.org/2020/formulas/mathematics/middle-school/zd4ptp7qnnk34sl97m1kknxn5djuz0oh9s.png)
The y-intercept is
![b=\$36](https://img.qammunity.org/2020/formulas/mathematics/middle-school/hbnos33l76cub5cbdss9qpaju433hskybv.png)
so
![y=0.42x+36](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qxsm6ro634q0zthwiisyj5zdntlzy853ht.png)
For x=78 miles
substitute in the linear equation and solve for y
![y=0.42(78)+36](https://img.qammunity.org/2020/formulas/mathematics/middle-school/15an71pkjialgwqszc9heqo0ivdm7q1ay5.png)
![y=\$68.76](https://img.qammunity.org/2020/formulas/mathematics/middle-school/dx7019k4fv0164tm892r66rmp2kv4sm5ql.png)
Part 4) Let
x ----> Alice's normal hourly rate
we know that
40 hours multiplied by her normal hourly rate plus 10 hours (50 h-40 h) multiplied by 1.5 times her normal hourly rate must be equal to $660
so
The linear equation that represent this situation is
![40x+10(1.5x)=660](https://img.qammunity.org/2020/formulas/mathematics/middle-school/d7w3mojmni7schs71re91ur3am08ki6wwk.png)
solve for x
![40x+15x=660](https://img.qammunity.org/2020/formulas/mathematics/middle-school/i4ocpkauxu7iqhuov9zje458q22ltc7w7b.png)
![55x=660](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ogw0ll0ql78je20zi3cam4f0qgfpydettv.png)
Divide by 55 both sides
![x=\$12\ per\ hour](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6yuingctwzu3g0e8bjaszd2951boym6sep.png)
Part 5) Let
x ----> the cost of one print
we know that
The cost of one print multiplied by 27 prints must be equal to $242.73
so
The linear equation is equal to
![27x=242.73](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ey37cac8j0zl6akku08ssoedexnqgqzik4.png)
solve for x
Divide by 27 both sides
![x=\$8.99](https://img.qammunity.org/2020/formulas/mathematics/middle-school/9uyyr3l4rqbbwovkmsl1j1p0zinzbdcl23.png)
Part 6) we know that
The linear equation in slope intercept form is equal to
![y=mx+b](https://img.qammunity.org/2020/formulas/mathematics/high-school/8nudzfk4b5l0arb9iixag2w8am6zn99zlr.png)
where
m is the slope or unit rate
b is the y-intercept or initial value
Let
y ----> the total cost
x ----> the number of classes
we have
Members
The slope is
![m=\$7\ per\ class](https://img.qammunity.org/2020/formulas/mathematics/middle-school/oa27zcctv7xrqh178xkm8r4i8xlt7umo5x.png)
The y-intercept is
![b=\$120](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rxjv66w8rqhfh06xhbilwupfjud1kl8ha2.png)
so
----> equation A
Non-Members
The slope is
![m=\$11\ per\ class](https://img.qammunity.org/2020/formulas/mathematics/middle-school/5j7d4hkd3ci7ivaexe61ee4w675qpjw40z.png)
so
----> equation B
To find out how many classes would a member have to take to save money compared to taking classes as a non-member, solve the following inequality
![7x+120 < 11x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xizcjp73zicmlekaoa6ufqiczx7yms5f3m.png)
Solve for x
subtract 7x both sides
![120 < 11x-7x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/yrczomn1a0s1ohyawzwhemrqng9wkirv4h.png)
![120 < 4x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/jhm5g62v90xr36tzcxpxzlebw0vbeje8hx.png)
Divide by 4 both sides
![30 < x](https://img.qammunity.org/2020/formulas/mathematics/middle-school/lscetr11pcyhkj431c32xjir5q8ym5yzl4.png)
Rewrite
![x > 30](https://img.qammunity.org/2020/formulas/mathematics/middle-school/quy5bkd9kxjt3o0at9z6zlec7n0ze56u00.png)
therefore
The number of classes must be greater than 30