4.7k views
3 votes
PleaseeeeeHelp!!!!!!!!!!!!

PleaseeeeeHelp!!!!!!!!!!!!-example-1
User Nerissa
by
7.4k points

1 Answer

3 votes

Answer:

x = -2, y = -5

Explanation:

Isolate x for 3x - 2y = 4

3x - 2y = 4

Add 2y to both sides

3x -2y + 2y = 4 + 2y

Simplify

3x = 4 + 2y

Divide both sides by 3


(3x)/(3) =(4)/(3) +(2y)/(3)

Simplify


x=(4+2y)/(3)

Now we substitute
x=(4+2y)/(3) for x in 4x - 3y = 7


4*(4+2y)/(3)-3y=7

Isolate y for
4*(4+2y)/(3)-3y=7


4*(4+2y)/(3)-3y=7

Expand
4*(4+2y)/(3)-3y


4*(4+2y)/(3) =(16+8y)/(3)


4*(4+2y)/(3)

Multiply fractions:
a*(b)/(c) =(a*b)/(c)


=((4+2y)*4)/(3)

Expand
(4+2y)*4


=4(4+2y)

Apply the distributive law:
a(b+c)=ab+ac


a=4, b=4,c=2y


=4*4+4*2y

Simplify
4*4+4*2y

Multiply the numbers:
4*4 = 16


=16+4*2y

Multiply the numbers:
4*2=8


=16+8y


=(16+8y)/(3)


=(8y+16)/(3)-3y

Convert element to fraction:
3y=(3y3)/(3)


=(16+8y)/(3) -(3y*3)/(3)

Since the denominators are equal, combine the fractions:
(a)/(c)±
(b)/(c)= (a±b)/(c)


=(16+8y-3y*3)/(3)


16+8y-3y*3

Multiply the numbers:
3*3=9


=16+8y-9y

Add similar elements:
8y-9y=-y


=16-y


=(16-y)/(3)

Apply the fraction rule:
(a)/(c)±
(b)/(c)= (a±b)/(c)


(16-y)/(3) =(16)/(3) -(y)/(3)


=(16)/(3)-(y)/(3)


(16)/(3) -(y)/(3) =7

Multiply both sides by 3


(16)/(3)*3-(y)/(3) *3=7*3

Simplify


16-y=21

Subtract 16 from both sides


16-y-16=21-16

Simplify


-y=5

Divide both sides by -1


(-y)/(-1) =(5)/(-1)

Simplify


y=-5

For
x=(4+2y)/(3) substitute
y=-5


x=(4+2y(-5))/(3)

Remove parentheses:
(-a)=-a


=(4+2y*5)/(3)

Multiply the numbers:
2*5=10


=4-10

Subtract the numbers:
4-10=-6


=-6


=(-6)/(3)

Apply the fraction rule:
(-a)/(b) =-(a)/(b)


=-(6)/(3)

Divide the numbers:
(6)/(3)=2


=-2

The solutions to the system of equations are


y=-5,x=-2

Checking answers

Plug in
x=-2 and
y=-5 into
3x-2y=4 and
4x-3y=7


3(-2)-2(-5)=4

Remove parentheses:
(-a)=-a,-(-a)=a


=3*2+2=5

Multiply the numbers:
3*2=6


=-6+2*5

Multiply the numbers:
2*5=10


=-6+10

Add/subtract the numbers:
-6+10=4


=4

First equation proven true

Substitute the values of x and y into the second equation


4(-2)-3(-5)=7

Follow the PEMDAS order of operations

Multiply and divide left to right
4(-2)


4(-2)

Apply rule
a*(-b)=-a*b


4(-2)=-4*2=-8


=-8


=-8-3(-5)

Multiply and divide left to right
3(-5)


3(-5)

Apply rule
a*(-b)=-a*b


3*(-5)=-3*5=-15


=-15


=-8-(-15)

Add and subtract left to right
-8-(-15)


-8-(-15)

Apply rule
-(-a)=+a


-(-15)=+15


=-8+15


-8+15=7


=7

Second equation proven true.

Both equations are true with
x=-2 and
y=-5

User Kashief
by
6.0k points