Solve the system of linear equations by elimination.

x + y = 1

5x + 3y = -3

Hello from MrBillDoesMath!

x = -3, y = 4

Discussion:

x + y = 1     =>

y = 1 -x

Substitute this y value into the second equation:

5x + 3y = -3           =>

5x + 3(1-x) = -3      => 3(1-x) = 3 -3x

5x + 3 - 3x = -3      => 5x -3x = 2x

2x + 3 = -3              => subtract 3 from both sides

2x       = -3 -3 = -6  => divide both dies by 2

x = -6/2 = -3

As x+y = 1, (-3) + y = 1 => y = 1 + 3 = 4

Thank you,

MrB