Question

100 points!

At what point(s) do these graphs intersect? y=x^2 = 3x-5
y=4x+1
Seth’s solution:
y=x^2 +3x-5
y=4x+1
x^2 =3x-5=4x+1
x^2 -x-6=0
(x-3)(x+2)=0
x=3 and x=-2
The graphs intersect at (-2,0) and (3,0).
Is Seth's solution correct? Explain.

Answer 1

Seth's answer is incorrect.

Explanation:

He is correct with all of his steps until he reaches the roots... the correct roots are, y = 4(3) + 1 = 13 y = 4(-2) + 1 = -7

So the correct answer would actually be: The graphs intersect at the coordinates (3,13) and (-2,-7)

Answer 2

Solution is correct till finding the roots:

• x = 3, x = -2

Then Seth should find the respective y- points using either equation:

• y = 4*3 + 1 = 13

and

• y = -2*4 + 1 = -7

Correct solution is:

• (3, 13) and (-2, -7)