Question

(3x-20)(4x-36) valve of x is what

Answer 1

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✪QUESTION✪:-

(3x-20)(4x-36) valve of x is

✪ANSWER✪:-

➠(3x-20)(4x-36)

➠(3x)(4x) + (3x)(-36) + (4x)(-20) +(-20)(-36)

➠12x² - 108x -80x + 720

➠12x ( x- 9) -80(x-9)

➠(x-9) (12x -80)

➠x-9 = 0

➠x=9

➠12x -80 = 0

➠12x = 80

➠x = 80/12

➠x = 20/3

therefore,

• x = 20/3
• x = 9

Answer 2

$\sf\huge\bold{Solution}$

$\sf \longmapsto(3x - 20)(4x - 36)$

$\sf \longmapsto3x(4x - 36) - 20(4x - 36)$

$\sf \longmapsto12 {x}^{2} - 108x - 80x + 720$

$\sf \longmapsto12 {x}^{2} -188x + 720 = 0$

Taking 2 common from the Equation

$\sf \longmapsto6 {x}^{2} - 94x + 360 = 0$

Again taking 2 common from the equation

$\sf \longmapsto3 {x}^{2} - 47x + 180 = 0$

Now ,it is in the form of a quadratic equation so ,we factorise it by middle term splitting method.

180×3=540

factors of 540=2×2×5×3×3×3

$\sf \longmapsto3 {x}^{2} - 27x - 20x + 180$

$\sf \longmapsto3x(x - 9) - 20(x - 9) = 0$

$\sf \longmapsto(3x - 20)(x - 9) = 0$

$\sf \: 3x - 20 = 0$

$\sf \boxed{ \bold{\: x = \dfrac{20}{3} }}$

$\sf \: x - 9 = 0$

$\sf \boxed{\bold{x = 9}}$