Question

factorise x²-x-72 by splitting the 'x' term method​

Answer 1

Question:-

Factorize x²- x - 72 by splitting the 'x' term method.

Solution:-

➣ x² - x - 72 = 0

➣ x² - 9x + 8x - 72 = 0

➣ x( x - 9 ) + 8( x - 9 ) = 0

➣ (x + 8) (x - 9) = 0

➣ x + 8 = 0 ; x - 9 = 0

➣ x = -8 ; x = 9

➣ $\boxed{x \: = \: 9}$

Verification:-

Take x = -8

Then,

➣ x² - x - 72 = 0

➣ -8² - ( -8 ) - 72 = 0

➣ 64 + 8 - 72 = 0

➣ 72 - 72 = 0

➣ 0 = 0

Now,

Take x = 9

➣ x² - x - 72 = 0

➣ 9² - 9 - 72 = 0

➣ 81 - 9 - 72 = 0

➣ 81 - 81 = 0

➣ 0 = 0

Answer 2

Question:-

Factorize x²- x - 72 by splitting the 'x' term method.

Solution:-

➣ x² - x - 72 = 0

➣ x² - 9x + 8x - 72 = 0

➣ x( x - 9 ) + 8( x - 9 ) = 0

➣ (x + 8) (x - 9) = 0

➣ x + 8 = 0 ; x - 9 = 0

➣ x = -8 ; x = 9

➣ \boxed{x \: = \: 9}

x=9

Verification:-

Take x = -8

Then,

➣ x² - x - 72 = 0

➣ -8² - ( -8 ) - 72 = 0

➣ 64 + 8 - 72 = 0

➣ 72 - 72 = 0

➣ 0 = 0

Now,

Take x = 9

➣ x² - x - 72 = 0

➣ 9² - 9 - 72 = 0

➣ 81 - 9 - 72 = 0

➣ 81 - 81 = 0

➣ 0 = 0