①2×5分之24-6y+5y=242×24/5-6y+5y=2448/5-y=24-y=24-48/5-y=（120-48）/5-y=72/5y=-72/5y=-14.4代入方程左边=2*24/5-6*（-72/5）+5*（-72/5）=48/5+72/5=24与右边相等 ②2×6分之39-3y+4y=37 2×39/6+y=37y=37-13...