`a, 3(7+48:x)=45`
`7+48:x=45:3`
`7+48:x=15`
`48:x=15-7`
`48:x=8`
`x=48:8`
`x=6`
Vậy `x=6`
`b, (x-55).28=0`
`x-55=0:28`
`x-55=0`
`x=0+55`
`x=55`
Vậy `x=55`
`c, 4^(2x)=16`
`4^(2x)=4^2`
`⇒2x=2`
`x=2:2`
`x=1`
Vậy `x=1`
`d, 5^(2x-3)-2.5^2=5^2 . 3`
`5^(2x-3)=5^2 . 3+2.5^2`
`5^(2x-3)=5^2 . (3+2)`
`5^(2x-3)=5^2 . 5`
`5^(2x-3)=5^3`
`⇒2x-3=3`
`2x=3+3`
`2x=6`
`x=6:2`
`x=3`
Vậy `x=3`
`e, 219-7(x+1)=100`
`7(x+1)=219-100`
`7(x+1)=119`
`x+1=119:7`
`x+1=17`
`x=17-1`
`x=16`
Vậy `x=16`
(nhớ cho chị hay nhất nha em)
Chúc em học tốt!!!
`@Nhi`
