Question

How do you solve this (first equation) x=2y-1 (second equation) x+y=40

Answer 1

`x = 26 (1)/(3) \\`

`y = 13 (2)/(3) \\`

Explanation:

x = 2y - 1

x - 2y = -1 ________(1)

x + y = 40________(2)

(2) - (1)

`x + y - (x - 2y) = 40 - ( - 1) \\ x + y - x + 2y = 40 + 1 \\ 3y = 41 \\ y = (41)/(3) \\ y = 13 (2)/(3) \\`

y = 13 2/3

`x + y = 40 \\ x + 13 (2)/(3) = 40 \\ x = 40 - 13 (2)/(3) \\ x = 40 - (41)/(3) \\ x = (3(40) - 41)/(3) \\ x = (120 - 41)/(3) \\ x = (79)/(3) \\ x = 26 (1)/(3) \\`