(1) x - y = 2 x+ y = 8 x^2-y^2 = (x+y)(x-y) = 8×2 = 16
(2) a + b = 2×2 = 4 [1] x + y = 3×1 = 3 [2] x - y = 4×6 = 24 [3] a - b = 2×5 = 10 [4] Eliminasi persamaan 1 dan 4 a+b=4 a-b =10 ______+ 2a = 14 a = 7 maka b = -3
Eliminasi Persamaan 2 dan 3 x+y=3 x-y=24 ______+ 2x=27 x = 27/2 maka x+y = 3 27/2 + y = 3 27/2 + y = 6/2 y = (6-27)/2 y = -21/2
Verified answer
(1) x - y = 2x+ y = 8
x^2-y^2 = (x+y)(x-y)
= 8×2 = 16
(2) a + b = 2×2 = 4 [1]
x + y = 3×1 = 3 [2]
x - y = 4×6 = 24 [3]
a - b = 2×5 = 10 [4]
Eliminasi persamaan 1 dan 4
a+b=4
a-b =10
______+
2a = 14
a = 7
maka b = -3
Eliminasi Persamaan 2 dan 3
x+y=3
x-y=24
______+
2x=27
x = 27/2
maka
x+y = 3
27/2 + y = 3
27/2 + y = 6/2
y = (6-27)/2
y = -21/2
ax-by
7×27/2 - -3×-21/2
189/2 - 63/2
126/2
= 63
semoga membantu :)