Question

Write the equation in factored form:

so x= what values?

What do the solutions for x mean?

x2−4x−21=0

Answer 1

x2 - 4x -21=0
For factorising first split the middle
term - 4x as - 7x and + 3x as -7x + 3x
- 4x and (-7x) (3x) = - 21 x2
=×2-7× +3x -21=0
= x (x-7) + 3(x -7) = 0
= (x + 3) (x - 7) = 0
Hence. the factors of x2 - 4x - 21 =
O are (x + 3) and (x - 7).