Question

a) 4x(2x-3) = 5x(x+3)

b) 2x(3x-4)= - (x+2)

Answer 1

A) 4x(2x-3) = 5x(x+3)

4x^2 - 12x = 5x^2 + 15x ==> 5x^2 - 4x^2 + 15x + 12x = 0

x^2 + 27x = 0

x1(x + 27 ) = 0

x1 = 0 

x2 + 27 = 0 ==> x2 = - 27
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b) 2x(3x-4)= - (x+2)

6x2 - 8x = - x - 2

6x2 - 8x + x + 2 = 0 ==> 6x2 - 7x + 2 = 0

Δ = 7²- 4.6.2 = 49 - 48 = 1


x = 7+/-1 ==> x = 7+/-1
        2.6                 12

x1 = 8         ; x2 =  6
       12                  12