`@` `\text {Ans}`
`\downarrow`
`a)`
`4x = 320 \div 16`
`=> 4x = 20`
`=> x = 20 \div 4`
`=> x=5`
Vậy, `x=5`
`b)`
`(x-10) \div 5 = 2`
`=> x - 10 = 2*5`
`=> x - 10 = 10`
`=> x = 10 + 10`
`=> x=20`
Vậy, `x=20`
`c)`
`(20+x) \div 5 = 25`
`=> 20+x = 25*5`
`=> 20+x = 125`
`=> x = 125 - 20`
`=> x = 105`
Vậy, `x=105.`
`@` `\text {Kaizuu lv uuu}`