Sagot :
x²+4x=36-5x
x²+9x-36=0
x²+12x-3x-36=0
x(x+12)-3(x+12)=0
(x-3)(x+12)=0
x-3=0 ⇒x=3
or
x+12=0⇒x=-12
x²+9x-36=0
x²+12x-3x-36=0
x(x+12)-3(x+12)=0
(x-3)(x+12)=0
x-3=0 ⇒x=3
or
x+12=0⇒x=-12
x²+4x+5x-36=0 [transpose]
x²+9x-36=0 [add like terms]
(x-3) (x+12)=0 [factors of -36 that will be 9 {from 9x} if added, when multiplied, will be same with the equation]
x-3=0 x+12=0 [transpose]
x=3 x=-12
x²+9x-36=0 [add like terms]
(x-3) (x+12)=0 [factors of -36 that will be 9 {from 9x} if added, when multiplied, will be same with the equation]
x-3=0 x+12=0 [transpose]
x=3 x=-12