Simultaneous equations can be solved either using substitution or elimination.
For this example we will use substitution to work out the answer, which will involve rearranging one of the equations (in this case the second equation is it is simpler) into a way that it can be inserted (or substituted) into the first equation.
Rearrange x-7-y=-3 into x-4=ySubstitute x-4=y into the first equation to make 3x+ (x-4) = 24Simplify this new equation into 4x -4 = 24 which simplifies into 4x=28 which means that x = 7
Substitute x=7 into the either of the equation (preferably the simpler equation) and simplify to find y(7) - 7 - y= -3 -y = -3y = 3
Answer y=3, x=7