5(x-2.5)=25.5x-2.5=25.5÷5x-2.5=5.1x=5.1+2.5x=7.6
5(x-2.5)=25.55x-12.5=25.55x=38x=7.6
x²-2x³=x²(1-2x)3y³-6y²+3y=3y(y²-2y+1)=3y(y-1)²a²(x-2a)²-a(x-2a)²=a(x-2a)²(a-1)第一所鼻后孔闭锁
x-2.5=25.5/5x-2.5=5.1x=5.1+2.5x=7.6
5(7.6-2.5)=25.5