10.5-25%x=1.5 25%x=10.5-1.5 25%x=9x=9÷25%x=9÷1/4x=9×4x=36
10.5-25%x=1.5 10.5-1.5=0.25xX=36
25%x=10.5-1.5=9x=9÷25%=36
看
X=36