(1)4x-3.6x=36, 0.4x=36, 0.4x÷0.4=36÷0.4, x=90; (2)5(x+1.5)=17.5, 5(x+1.5)÷5=17.5÷5, x+1.5=3.5, x+1.5-1.5=3.5-1.5, x=2.