Giải thích các bước giải:
`6x(2x-5)+60=12x^2`
`=>12x^2-30x+60=12x^2`
`=>-30x+60=0`
`=>30x=60`
`=>x=2`
`4x(5-4x)+16x^2=4-30`
`=>20x-16x^2+16x^2=-26`
`=>20x=-26`
`=>x=-13/10`
`3x+2(5-x)=-11`
`=>3x+10-2x=-11`
`=>x+10=-11`
`=>x=-21`
`5x(2x-7)+2x(8-5x)=5`
`=>10x^2-35x+16x-10x^2=5`
`=>-19x=5`
`=>x=-5/19`