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Please show work on how to find the points we graph

Please show work on how to find the points we graph-example-1
User Ngj
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1 Answer

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we have the system

y < -x^2-x+8 ------> inequality A

the solution for this inequality is the shaded area below the dashed quadratic equation

and

y > x^2+2 -----> inequality B

the solution for this inequality is the shaded area above the dashed quadratic equation

therefore

the solution of the system is the intersection of both areas

see the attached figure to better understand the problem

To find out the intersection points of both graphs, solve the system of equations

y=-x^2-x+8 ------> equation 1

y=x^2+2 ------> equation 2

solve the system by elimination

Adds equation 1 and equation 2

y=-x^2-x+8

y=x^2+2

----------------

2y=-x+10 ------> y=-(1/2)x+5 -----> equation 3

substitute the equation 3 in equation 1 or equation 2 to obtain the values of x

-(1/2)x+5=x^2+2

x^2+(1/2)x-3=0 ------> solve the quadratic equations

the values of x are

x=-2 and x=1.5

to obtain the values of y

substitute the values of x in equation 3

so

For x=-2

y=-(1/2)(-2)+5 ------> y=6

point (-2,6)

For x=1.5

y=-(1/2)(1.5)+5 ------> y=4.25

point (1.5,4.25)

the other two points are the y-intercepts of the quadratic equations

Please show work on how to find the points we graph-example-1
User Sanjayr
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3.0k points