`a)5−15−(−4+2)−7`
`=5−15−(−2)−7`
`=5−15+2−7`
`=−10+2−7`
`=−8−7`
`=−15`
`b)−18:3−2.5−|−17|`
`=−6−10−17`
`=−16−7`
`=23`
`c)2.|x+1|−4=−2−(−12)`
`2.x+1−4=−2+12`
`2.x+1−4=10`
`2.x+1=10+4`
`2.x+1=14`
`2.x=14−1`
`2.x=13`
`x=13:2`
`x=6,5`
`d)(3x)/4−2=1,5.(x+75%)`
`⇔3/4x−2=3/2(x+3/4)`
`⇔3/4x−2=3/2x+9/8`
`⇔3/4x−3/2x=2+9/8`
`⇔−3/4x=25/8`
`⇔x=−25/6`
`e)1/3.(x−2 1/2)^2−2 3/4=−2`
`1/3.(x−5/2)^2−11/4=−2`
`1/3.(x−5/2)^2=−2+11/4`
`1/3.(x−5/2)^2=3/4`
`(x−5/2)^2=3/4:1/3`
`(x−5/2)^2=9/4`
`(x−5/2)^2=3/(2^2)` hay `(x−5/2)^2=(−3/2)^2`
`x−5/2=3/2+5/2` `x−5/2=−3/2`
`x=4` `x=−3/2+5/2`
`x=1`
Vậy `x=4` hay `x=1`
`color{red}{Rusian}`
