Question

1.Metode subsitusi
3x+4y+2=0
Dan 2x-y+5=0..

Answer 1

3x + 4y + 2=0
3x+4y=-2

2x-y+5=0
2x-y=-5
-y = -5-2x
y=5+2x

3x+4y=-2
3x + 4(5+2x) =-2
3x +20+8x=-3
11x = -3-20
11x = -23
x = -23/11

y= 5+2(-23/11)
= 5 -46/11
= 55-46 / 11
= 9/11

Answer 2

3x+4y+2=0
3x+4y= -2

2x-y+5=0
2x-y= -5

3x+4y= -2
2x-y = -5 ( dikurang )
x+5y = 3
x = 3 - 5y

f(x)= 2x-y = -5
= 2(3 - 5y) - y = -5
= 6 - 10y - y = -5
= -11y = -5 - 6
= 11 y = 11
y= 11/11
y= 1


f(x) = 2x-y = -5
= 2x-1 = -5
= 2x = -5 + 1
x = 4/2
x = 2