a)3x(x-5)-(x+1)(3x-2)=34
3x² -15x-3x²+2x-3x+2=34
-16x=32
x=-2
b)8x(x-2)-3(x+1)(x-5)-5x²=3
8x² -16x-3(x²-5x+x-5)-5x²=3
8x²-16x-3x²+12x+15-5x²=3
-4x=-12
x=3
c)2(x+1)(x-5)-2x(x-3)=-2
2(x²-5x+x-5)-2x²+6x=-2
2x²-8x-10-2x²+6x=-2
-2x=8
x=-4
d)(x+1)(x²+2x-1)-x²(x+3)=4
x³+2x²-x+x²+2x-1-x³-3x²=4
-x=5
x=-5
CHÚC BẠN HỌC TỐT!!!-FROM THANH
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