Question

$5x2 - 4 - 8x$
by using middle term factor
​

Answer 1

Question:-

Factorise 5x² - 4 - 8x

Answer:-

5x² - 4 - 8x

=> 5x² - 8x - 4

We have to find two numbers so that their sum is -8(coefficient of x) and their product is {5(coefficient of x²) * -4(constant term)}= -20

Such numbers are -10 and +2 ==> -10 + 2 = -8 and -10 * +2 = -20

=> 5x² - 10x + 2x - 4

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

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

Ans. = (x - 2)(5x + 2)