Question

Stuck... please help. I need to factor the following:

h(x) = 7x^2 - 5x -2

Answer 1

the factors will look like
(7x + a)( x + b)

where a times b will equal -2

and the middle term -5x will be obtained on expanding the factors

Answer 2

so a and b will be either -2 and +1 or +2 and -1

does that help you?

Answer 3

lets try expanding one combination

(7x - 2)(x + 1) - first multiply second bracket by 7x then by -2:

= 7x*x + 7x*1 - 2*x -2*1

= 7x^2 + 7x - 2x - 2
= 7x^2 + 5x - 2

- this is not correct so we picked the wrong combination
- the + 1 has to be with the 7x and -2 is with the x

answer is (7x + 2)(x - 1)

Answer 4

Hmm, the answer is correct but my book derives at the answer 7(x-1)(x+2/7). I guess they both do (?).

Answer 5

yes - both right