solve the system a+b=4 and a-2*b=1 — step-by-step solution

We have the following 2 equations:

[1]:

a + b = 4

[2]:

a - 2 b = 1

Solving for a:

a + b = 4

[1]

a + b = 4

Solution found [1]:

a = 4 - b

Solving for b:

a - 2 b = 1

[2] where

a = 4 - b

4 - 3 b = 1

- 3 b = 1 - 4

- 3 b = -3

3 b = 3

b = \frac{3}{3}

Solution obtained [2]:

b = 1

You can compute the value of a based on:

a = 4 - b

using

b = 1

a = 4 - 1

Solution obtained:

a = 3

▷Answer: ${a = 3, b = 1}$