7x（3-x）=4（x-3）7x（3-x)+4(3-x)=0(3-x)(7x+4)=0x1=3 x2=-4/7 4(x-3)²-25（x-2）²=0(2x-6+5x-10)(2x-6-5x+10)=0(7x-16)(4-3x)=0x1=16/7 x2=4/34x²-4x+1=0 (2x-1)²=02x-1=0x=1/2
x=-3/7 或x=4x=16/7或x=4/3x=1/2
