Anthony P. answered • 03/13/13

Experienced tutor in earth sciences and basic math to trigonometry

(1) 7y = x + 2

(2) 4x - 8y = 12

To solve this system, let's choose a variable from on of the equations to solve for (it doesn't matter which equation or which variable, so let's make it easy). I'll choose to solve for x in eqn 1.

x = 7y - 2

Now substitute for **x** in eqn 2

4**x** - 8y = 12

4**(7y - 2)** - 8y = 12

Notice that now we have an equation that's only in terms of one variable, y. Solve for y.

28y - 8 - 8y = 12

20y = 20**y = 1**

Now that we have a value for y, substitute into any equation to find x (I'll use x = 7y - 2 since it was already solved for x)

x = 7y - 2**x = 7(1) - 2 = 5**

So the point of intersection of these two lines is **(5 , 1)**