Question

2. Solve by factoring?

a) x2 + x - 20 = 0
b) x = 36
c) *+ 12x = -36
d) x = 10x

Answer 1

Explanation:

1. a :

• x²+x-20 = 0
• to factor we can calculate the dicriminant
• we get 81
• so we have two solutions
• after factoring using the dicriminant we get : (x+5) (x-4)
• so x= 4 or x= -5
• b :
• x= 36
• x-36 = 0
• x-6²=0
• (√x+6)(√x-6) = 0
• √x = 6 or √x= -6 ( impossible for real numbers)
• x= 6²
• x= 6
• d:
• x= 10x
• x-10x=0
• x(1-10) = 0
• -9x = 0
• x= 0