x + y = 9

2x+2y = 18

To check if (1,8) is a solution to this system, just plug the numbers into the equation

First let's check the first equation

**1 + 8 = 9 **add 1 and 8

By adding, you should get

**9 = 9 **since this equation is true we should check the second equation

**2 ( 1 ) + 2 ( 8 ) = 18 **multiply 2 with 1 and 2 with 8

By multiplying, you should get

**2 + 16 = 18 **add 2 with 16

By adding, you should get

**18 = 18 **this equation is true also

Since both of the equation were true, that means **(1,8)** **is a solution to this set**

We'll re-write the 2nd equation, dividing it by 2 both sides:

2x + 2y = 18 => x + y = 9

To verify if a pair of values represents the solution of a system, we need to substitute the values withind the equations of the system.

Therefore, we'll replace x and y by 1 and 8,within the 1st equation. We could replace the values within the 2nd equation, as well, since the 1st equation is equal to the 2nd one.

1 + 8 = 9

9 = 9

**Since the equations are verified, then the pair of values (1 ; 8) represents the solution of the given system.**