Find the intercepts of the function y= x^2 -7x -8 = 0

2 Answers | Add Yours

justaguide's profile pic

justaguide | College Teacher | (Level 2) Distinguished Educator

Posted on

We need to find the intercepts of the function y= x^2 -7x -8

The graph of the function intercepts the x-axis where y = 0

x^2 - 7x - 8 = 0

=> x^2 - 8x + x - 8 = 0

=> x(x - 8) + 1(x - 8) = 0

=> (x + 1)(x - 8) = 0

x = -1 and x = 8

Now if we equate x = 0, we get the point where the graph intercepts the y-axis.

y= 0^2 -0*x -8

=> y = -8

The x-intercepts of the graph given by the function are (-1,0) and (8, 0) and the y-intercept is (0, -8)

hala718's profile pic

hala718 | High School Teacher | (Level 1) Educator Emeritus

Posted on

Given the function y= x^2 - 7x -8

We need to find the intercepts.

First we will determine the x-intercept.

The x-intercept is the point where the fnction  meets the x-axis.

Then the values of y will be 0.

==> x^2 - 7x -8 = 0

==> (x-8)(x+1) = 0

==> x1 = 8

==> x2= -1

Then we have two x-intercepts: (8, 0) and (-1, 0)

Now we will determine the y-intercept.

The y-intercept is the point where the function meets the y-axis, then the value of x is 0.

==> y= 0 - 0 -8 = -8

Then the y-intercept is the point (0, -8)

Then the intercepts are:

x-intercepts are (8, 0) and (-1,0)

y-intercept is ( 0, -8)

We’ve answered 318,936 questions. We can answer yours, too.

Ask a question