Question

I need help with number 9

Answer 1

XY ≡≡ XZ

9a² - 30 = 3a

3a² - 10 - a = 0

3a² - a - 10 = 0

a = 1 ± √[1 –4(3)(-10))]/2(3)

a = ⅙ ± √[ 1 + 120]/6

a = ⅙ ± √[121]/6

a = ( 1 ± 11)/6.... taking the positive.

a = 12/6

a = 2 (^^)