Answer:
(5x - 3)(7x + 4) .
Explanation:
35x^2 - x - 12
= 35x^2 - 1x - 12
Now we multiply the first coefficient by the last:
35 * -12 = -420.
We need 2 values whose product is -420 and whose sum = the coefficient of x ( -1).
These are 20 and -21, so we rewrite the original expression as:
35x^2 + 20x - 21x - 12 Now we try to factor by grouping
5x(7x + 4) - 3(7x + 4) 7x + 4 is common so we have:
(5x - 3)(7x + 4) (answer).