How do you solve $x( 5x - 2) = 24$ ?

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Answer 1 · 2018-05-01T21:18:19

$x=12/5 or 2.4 , -2$

expand:

$x(5x-2) -> 5x^2-2x=24$

set equal to $0$ :

$5x^2-2x=24 -> 5x^2-2x-24=0$

factorise:

$-> 5x^2+10x-12x-24$

$-> 5x(x+2)-12(x+2)$

$rArr (x+2)(5x-12)$

Check to see if correct:

$(5x-12)(x+2)=5x^2+10x-12x-24$

$-> 5x^2-2x-24$ .

set each bracket equal to $0$ :

$5x-12=0$

$-> 5x=12$

$rArr x=12/5$

$x+2=0$

$rArr x=-2$

Check these values:

$2.4(5 xx 2.4-2)=2.4 xx 10=24$

$-2(5 xx-2-2)$ =-2 xx -12=24#

$therefore$ these values are correct.

How do you solve x( 5x - 2) = 24x( 5x - 2) = 24?