Question

Solve x2 − 8x − 20 = 0.

x = 4, x = −5

x = −4, x = 5

x = 2, x = −10

x = −2, x = 10

Answer 1

What do you get when you factor \(\large x^2 − 8x − 20\) ?

Answer 2

You can either factor it, or plug in each value and check BOTH make the equation equal zero.

ie if the equation is true for both x = 4, x = −5 (when you plug x=4 in, you get 0. And when you plug x=-5 in, you get zero), then that would be your answer.

Answer 3

10*-2=-20
and 10-2=8

Answer 4

\[x ^{2}-\left( 10-2 \right)x-20=0\]
\[x ^{2}-10x+2x-20=0,\]
make factors and get the solutions

Answer 5

Thank you guys! I figured it out :)

Answer 6

yw