(a,b) = ( a₁,b₁) dr sistem persamaan 2a-7b=-16 dan a+8b=15 maka nilai a₁+2b₁ adalah

2a-7b=-16
a+8b=15

penyelesaian:
a=15-8b

2a-7b=-16
2(15-8b)-7b=-16
30-16b-7b=-16
30-33b=-16
-33b=-16-30
-33b=-46
b= - 46:(-33)
b=1,3

a=15-8b
=15-8(1,3)
=15-10,3
=4,7

jadi,a+2b=4,7+2(1,3)
=4,7+2,6
=7,3

2a - 7b = -16 | x1
a + 8b = 15 | x2
2a - 7b = -16
2a + 16b = 30
-------------------- --
-23b = -46
b = -46/-23
b = 2

a + 8b = 15
a = 15 - 8b
a = 15 - 8(2)
a = 15 - 16
a = -1

(a,b) = (-1,2)
(a₁,b₁) = (-1,2)

a₁ + 2b₁ = -1 + 2(2) = 3

semoga membantu ^^