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The line y=x+1 intersects the graph of y=x^2-3x-11 at the points A and B

Find the coordinates of A and B

User Jake Badlands
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1 Answer

12 votes
12 votes

Answer:

(6, 7) and (-2, -1)

Explanation:

if y=x+1 intersects with y=x^2-3x-11

then we need to find x and y such that both of those equations are true.

If y = x + 1 is true and y=x^2-3x-11, then

y - y = x^2-3x-11 - x - 1 is also true

0 = x^2 - 4x - 12

use your preferred method to solve the quadratic equation

0 = (x - 6)(x + 2)

x = 6 or x = -2

now for each x we take y from either equation, but y = x + 1 is simpler.

for x = 6 the coordinates are (6, 7) and for x = -2 the coordinates are (-2, -1)

User Mark Elliot
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