1 x/4+x/3 = 7
3x/12 + 4x/12 = 7
7x/12 = 7
x/12 = 1
x = 12
2 2x/5 + x/2 = 9
4x/10 + 5x/10 = 9
9x/10 = 9
x/10 = 1
x = 10
3 5x/4 - x/2 = 3
5x/4 - 2x/4 = 3
3x/4 = 3
X/4 = 1
X = 4
4 4x/5 - x/10 = 7
8x/10 - x/10 = 7
7x/10 = 7
X/10 = 1
X = 10
5 3x/4 + 5x/6 = 38
9x/12 + 10x/12 = 38
19x/12 = 38
X/12 = 2
X= 12×2
X=24