急...唔識做-!!maths form4題目_!!

(3x+2)(x-5)+x(5-x)= 0
(3x+2)(x-5)-x(x-5) = 0
(x-5)(3x+2-x) = 0
x-5 = 0 or 2x + 2 = 0
x = 5 or x = -1
(4x-5)^2 = (x-9)(4x-5)
(4x-5)^2 - (x-9)(4x-5) = 0
(4x-5)[4x-5 - (x-9)] = 0
(4x-5)(3x+4) = 0
4x - 5 = 0 or 3x + 4 = 0
x = 5/4 or x = -4/3
Be careful to this!!!
(4x-5)^2 = (x-9)(4x-5)
(4x-5)^2 / (4x-5) = x - 9
4x - 5 = x - 9
3x = -4
x = -4/3 WRONG!!

(4x-5)^2 / (4x-5) = x - 9
is wrong... becuase you don't know the value of x...
and if 4x-5 = 0... then the equation becomes wrong...

(3x+2)(x-5)+x(5-x)= 0

=> (3x+2)(x-5)-x(x-5)= 0

=>(x-5)(3x+2-x)=0

=>(x-5)(2x+2)=0

=>x-5=0 or x+1=0

=>x=5 or x= -1//

(4x-5)^2 = (x-9)(4x-5)

=>(4x-5)^2-(x-9)(4x-5)=0

=>(4x-5)(4x-5-x+9)=0

=>(4x-5)(3x+4)=0

=>x=5/4 or x=-4/3//