To solve simulatenous equations there are two main methods, substitution and elimintion. The first method requires the principle where if x is equal to a number, say x=2 then we can substitute this in, for example 2x would equal 2 x 2 or 4. In this example we can rearrange the first example to state x = 10-2y. You can then substitute into the second equations using brackets to give 3(10-2y) + 2y=18. You can then solve the equation for a numerical value of y. Alternatively, elimination requires taking the equations away from each other if you have a common term for either x or y. Here you have 2y in both equations, so you can minus one from the other giving 3x-x=18-10. This can then be solved for a numerical value of x. In both examples you will then need to substitute the number back into the equation to find the other term.