Solve the simultaneous equations, 3x + y = 10 and x + y = 4.

Firstly we want to get both equations in terms of one variable.3x + y = 10y = 10 - 3
x + y = 4y = 4 - x
Make these two equations equal10 - 3x = 4 - x
Rearrange the numbers to one side and the x's to one side, remember to change the sign when you move across the equals sign10 - 4 = -x + 3x6 = 2x6/2 = x3 = x
Then substitute x=3 into one of the original equations.x + y = 43 + y = 4y = 4 - 3y = 1
The answers are x=1 and y=3