Question

factorise x2-3x-10

x2 is x squared

Answer 1

x²-3x-10

1) solve this equation:
x²-3x-10=0

x=[3⁺₋√(9+40)] / 2=(3⁺₋7) / 2

We have two solutions:

x₁=(3-7)/2=-4/2=-2          ⇒(x+2)
x₂=(3+7)=10/2=5             ⇒(x-5)

Therefore:
x²-3x-10=(x+2)(x-5)

Answer 2

x² - 3x - 10 = 0

(x - 5)(x + 2) = 0

x - 5 = 0 ⇒ x = 5
x + 2 = 0 ⇒ x = -2

(x - 5)(x + 2) = 0
x(x + 2) - 5(x + 2) = 0
x² + 2x - 5x - 10 = 0
x² - 3x - 10 = 0

x² ⇒ is x * x
Factors of 10 are:
1 x 10
2 x 5

-3 is indicative whether the factors will use a positive or negative sign.
to produce -3 the factors of 10 will be 2 and -5.