a.2x+2y=8 2x-3y=-7 2x=8-2y 8-2y-3y=-7 2x=8-2y -5y=-15 |÷(-5) 2x=8-2y y=3 2x=8-2*3 y=3 2x=2 y=3 x=1 y=3 b.4y+2x=10 3x+8y=10 4y=10-2x 3x+2(10-2x)=10 4y=10-2x 3x+20-4x=10 4y=10-2x -x=-10 4y=10-2x x=10 4y=10-2*10 x=10 4y=-10 x=10 y=-2,5 x=10 c.4a+2b=10 5a-2b=-10 a=(10-2b)÷4=2,5-½b 5(2,5-½b)-2b=-10 a=2,5-½b 12,5-2,5b-2b=-10 a=2,5-½b -4,5b=-22,5 a=2,5-½b b=5 a=2,5-2,5 b=5 a=0 b=5 d.5a+8b=14 4a+3b=1 -------------- a+5b=13 a=13-5b 5(13-5b)+8b=14 65-25b+8b=14 -17b=-51 b=3 a=13-5b a=-2 b=3 e.4(x-2)-(y-2)=1 10x-2y=18 4x-8-y+2=1 10x-2y=18 4x-y=7 10x-2y=18 y=4x-7 10x-2(4x-7)=18 y=4x-7 10x-8x+14=18 y=4x-7 2x=4 y=4x-7 x=2 y=4*2-7 x=2 y=1 x=2 f.2x-4(y+1)=10 2(x+3)-(1-y)=9 2x-4y-4=10 2x+6-1+y=9 2x-4y=14 2x+y=4 y=4-2x 2x-4(4-2x)=14 y=4-2x 2x-16+8x=14 y=4-2x 10x=30 y=4-2x x=3 y=4-2*3 x=3 y=-2 x=3
a. 2x+2y=8 I *(-1) 2x-3y=-7 -2x-2y=-8 2x-3y=-7 -5y=-15 y=3 2x+2*3=8 2x=8-6 2x=2 x=1 b.4y+2x=10 I *(-2) 3x+8y=10 -8y-4x=-20 8y+3x=10 -x=-10 x=10 4y+20=10 4y=-10 y=-10/4 c.4a+2b=10 5a-2b=-10 9a=0 a=0 2b=10 b=5 d.5a+8b=14 I * (-4) 4a+3b=1 I * 5 -20a - 32b = -56 20a+15b=5 -17b=-51 b=3 5a+24=14 5a=-10 a=-2 e.4(x-2)-(y-2)=1 10x-2y=18 4x-8-y+2=1 10x-2y=10 4x-y=7 I * (-2) 10x-2y=10 -8x+2y=-14 10x-2y=10 2x=-4 x=-2 -8-y=7 -y=15 y=-15 f.2x-4(y+1)=10 2(x+3)-(1-y)=9 2x-4y-4=10 2x+6-1+y=9 2x-4y=14 2x+y=4 I *(-1) 2x-4y=14 -2x-y=-4 -5y=10 5y=-10 y=-2 2x+8=10 2x=2 x=1
