Solve 2a + 5b = 2

Question

3a + 18b = 25

Answer 1

3 a + 18 b = 25
-
2 a + 5 b = 2
_______________
3 a - 2 a + 18 b - 5 b = 25 - 2

a + 13 b = 23

Subtract 13 b to both sides

a = 23 - 13 b

Put this value in equation:

2 a + 5 b = 2

2 ( 23 - 13 b ) + 5 b = 2

46 - 26 b + 5 b = 2

46 - 21 b = 2

Subtract 46 to both sides

- 21 b = - 44

Multiply both sides by - 1

21 b = 44

b = 44 / 21

a = 23 - 13 b

a = 23 - 13 • 44 / 21 =

23 - 572 / 21 = 483 / 21 - 572 / 21

a = - 89 / 21