You can put this solution on YOUR website! -3[5+2(-7+x)+x]= -3x -(x+3)
-3(5-14+2x+x)=-3x-x-3
-3(-9+3x)=-4x-3
27-9x=-4x-3
27-27-9x=-4x-3-27
-9x=-4x-30
-9x+4x=-30
-5x=-30
-5x/-5=-30/-5
x=6
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Check by plugging (x=6) back into the original equaiont and solve.