1) -17x+2y+3y+3x+4x=-10x+5y=-10*(-2.15)+5*0.04=21.5+0.2=21.7 2) -13x+16=2*(2x+25) -13x+16=4x+50 -13x-4x=50-16 -17x=34 x=34/-17 x=-2