數學問題 2題~!

當某數增加32%,再乘上80%,結果係1.9008.求某數.
設某數為x,
x*(1+32%)*80% = 1.9008
x*(1+32%) = 1.9008 / 0.8
x*1.32 = 2.376
x = 2.376 / 1.32
x = 1.8

8) 某數的3倍加上28,等於該數的5倍加上12.求某數.
設某數為x,
3x + 28 = 5x + 12　
2x = 16
x = 8

X (1+32%)(80%)=1.9008


3X+28=5X+12