Question

x square - 4 x is equal to 5

Answer 1

x² - 4x = 5


Adding - 5 on both sides,


x² - 4x + ( - 5 ) = 5 + ( - 5 )

x² - 4x - 5 = 0


Splitting - 4x in two terms such that their product become 5x.
4x = 5x - x


x² - ( 5x - x ) - 5 = 0

x² - 5x + x - 5 = 0

x( x - 5 ) + 1( x - 5 ) = 0

( x - 5 )( x + 1 ) = 0


By Zero Product Rule :-


x = 5 or x = - 1




Therefore the value of x satisfying the given equation is 5 or - 1 .



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Answer 2

x^2 - 4x = 5
x^2 - 4x - 5 =0
x^2 + x - 5x - 5 =0 
x(x+1) -5(x+1)=0
x= 5, -1