Solve the simultaneous equations: 2x + y = 18, x - y =6.

There are 2 different ways to approach solving simultaneous equations: 1) making x or y the subject of one of the equations.2) addition or subtraction method.In this section, I will explain the first method. So firstly, I'm going to refer to 2x+y=18 as equation 1, and x-y=6 as equation 2. Then you make either x or y the subject of one of the equations. In this case, it is easiest to make x the subject of equation 2. This gives x= 6+y. You then can sub (6+y) which is equal to x, into equation 1, which gives 2(6+y)+y=18. You then expand the brackets to give 12+2y+y=18, and simplify to give 3y=6, which means y=2. We can then sub this value of y straight into the rearranged form of equation 2, x=6+y, to give x=8. Sub both values back into both of the original equations to ensure the values for x and y are both correct.