Verified answer

a^2 – a – 20

= a^2 + 4a - 5a - 20

= a(a + 4) - 5(a + 4)

= (a + 4)(a - 5) Ans.

First factor:

a^2 - a - 20

a^2 + 4a - 5a - 20

a(a + 4) - 5(a + 4)

(a - 5)(a + 4)

You can't solve this because there is no equal sign. However if it was set equal to zero, you could solve it very easily. Just set each factor equal to 0 and solve for x in both factors:

a - 5 = 0

a = 5

a + 4 = 0

a = -4

The solutions (if this were a quadratic equation) would be a = -4, 5

If you mean a^2 - a - 20 = 0, we have

(a-5)(a+4) = 0

So, a = 5 or a = -4

a^2-a-20,

factor,

(a-5)(a+4),

zero property,

a-5=0, a+4=0,

a=0+5=5,

a=0-4=-4.

Answer: 5, -4.

This is not solveable. However, i can factor it.

(a - 5 )(a + 4 )