`#huy`
`a) 3(1 – 4x)(x – 1) + 4(3x + 2)(x + 3) = 38`
`<=>(3-12x)(x-1)+(12x+8)(x+3)-38=0`
`<=>3x-3-12x^2+12x+12x^2+36x+8x+24-38=0`
`<=>59x-17=0=>x=17/59`
`b) 5(2x + 3)(x + 2) – 2(5x – 4)(x – 1) = 75`
`<=>(10x+15)(x+2)-(10x-9)(x-1)-75=0`
`<=>10x^2+20x+15x+30-10x^2+10x+8x-8-75=0`
`<=>53x-53=0=>x=1`
`c) 2x^2 + 3(x – 1)(x + 1) = 5x(x + 1)^2`
`<=>2x^2+3(x^2-1)-5x^2-5x=0`
`<=>-3-5x=0=>x=(-3)/5`