12x+31=23x-22(x-2)-1=5(x-2)-7иy+20=-yРешите уровнения

12х+31=23х-2 12х-23х= -2-31 -11х= -33 х=3 2(х-2)-1=5(х-2)-7 2(х-2)-5(х-2)= -7+1 -3(х-2)= -6 х-2=-6: (-3) х-2= 2 х=4 у+20= -у у+у= -20 2у= -20 у= -10

[latex]1)12x+31=23x-2 \\ 12x-23x=-2-31 \\ -11x=-33 \\ x=3 \\ \\ 12*3+31=36+31=67 \\ 23*3-2=69-2=67 \\ 67=67 \\ \\ [/latex] [latex]2) 2(x-2)-1=5(x-2)-7 \\ 2x-4-1=5x-10-7 \\ 2x-5x=-10-7+4+1 \\ -3x=-12\\x=4 \\ \\ 2*(4-2)-1=2*2-1=4-1=3 \\ 5(4-2)-7=5*2-7=10-7=3 \\ 3=3[/latex] [latex]3)y+20=-y \\ y+y=-20 \\ 2y=-20 \\ y=-20/2 \\ y=-10 \\ [/latex]