#color(blue)(y=x+1# #2x+color(blue)y=7# #2x+color(blue)(x+1)=7# #3x+1=7# #3x=7-1=6# (we substract #1# on each side ) #color(red)x=6/3=color(red)2# (we divide by #3# on each side )
Now that we have #color(red)x#, we can find #color(blue)y# : #color(blue)y=color(red)x+1=color(red)2+1=color(blue)3#