解方程. 5x-7.8=20.2

解方程. 5x-7.8=20.2 3.5x+0.45=2.9 x÷3.4=10.2.
2025-02-25 19:53:04
推荐回答(1个)
回答1:

(1)5x-7.8=20.2,
5x-7.8+7.8=20.2+7.8,
5x=28,
5x÷5=28÷5,
x=5.6;

(2)3.5x+0.45=2.9,
3.5x+0.45-0.45=2.9-0.45,
3.5x=2.45,
3.5x÷3.5=2.45÷3.5,
x=0.7;

(3)x÷3.4=10.2,
x÷3.4×3.4=10.2×3.4,
x=34.68.