Question

Giai giúp em cau nay voi (2x+3)(x-5)=4x²+6x

 

Answer 1

(2x+3)(x-5)=4x^2 + 6x

<=> 2x^2 - 7x - 15 = 4x^2 + 6x

<=> 2x^2 + 13x + 15 = 0

<=> (2x^2 + 3x) + (10x+15) = 0

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

<=> x = -3/2

hoặc x = -5

Vậy...

Answer 2

<=>2x^2-7x-15-4x^2-6x=0 <=>-2x^2 -13x-15=0 <=>(2x^2-3x)+(-10x-15)=0 <=>x(2x-3)-5(2x+3)=0 <=>(x-5)(4x^2-9)=0 =>x-5=0 hay 4x^2-9=0 x=5 hay. 4x^2=9 x^2=9/4 =>x=3/2 Vậy x=5 hay x=3/2 k mình nha