x+ (-15) = 21
x= 21 - (-15)
x= 36
Vậy...
17x - ( -x-2) = 3x +47
17+ x +2 = 3x+47
19+x = 3x+47
19+x -3x = 47
19+ (-2x) = 47
-2x= 47-19
-2x=28
x= 28: ( -2)
x= -14
Vậy...
X + ( - 15 ) = 21
X = 21 + ( - 15 )
X = 6
a,Ta có :\(x+\left(-15\right)=21\)
\(\Leftrightarrow x=21-\left(-15\right)\)
\(\Leftrightarrow x=21+15\)
\(\Leftrightarrow x=36\)
Vậy \(x=36\)
x + ( - 15 ) = 21
\(x=21-\left(-15\right)=21+15=36\)
17x - ( -x-2) = 3x +47
\(17x+x+2=3x+47\)
\(17x+x-3x=47-2\)
\(15x=45\rightarrow x=3\)
Học tốt nhe:3