Question

Solve the system of equations. x1 + x2 + x3 = 7 x1 - x2 + 2x3 = 7 5x1 + x2 + x3 = 11

Answer 1

x1 =1

x2 =2

x3 =4

Explanation:

Given is a systems of equations in 3 variables.

No of equations given = 3

`x1 + x2 + x3 = 7 ... I\\x1 - x2 + 2x3 = 7 ... II\\5x1 + x2 + x3 = 11 ... III`

subtract equation 1 form equation 3

We get

`4x1=4\\x1=1`

Substitute this value in 2 and 3

`x2-2x3 = -6 ... iv\\x2+x3 =6 ... v`

subtract iv from v

3x3 = 12

x3=4

Substitute in v

x2 =2

solution is

x1 =1

x2 =2

x3 =4