Question

(x-2)(x 10)=13 a. x=3 b. x=8 c. x=10 d. x=11

Answer 1

( x - 2 ) ( x + 10 ) = 13
x ² + 10 x - 2 x - 20 = 13
x ² + 8 x - 33 = 0   (the quadratic  equation ):$x_{12} = \frac{-8\pm \sqrt{64 + 132} }{2}= \frac{-8\pm14}{2}$
x 1 = 3,  x 2 = -11
Answer: a ) x = 3  ( one solution )