(2.9x-0.5y)-(-2.9x-1.5y) (4x-8y)-(5x-12y) -1.4(0.2a-0.3b)+1.8a 1/2(-6.2a-1.6b)+b

2,9x-0,5y+2,9x+1,5y=5,8x+1y4x-8y-5x+12y=-1x+4y-0,28a+0,42b+1,8a=1,52a+0,42b-3,1a-0,8b+b=-3,1a+0,2b