Answer:
The answer you're looking for is x = 6, and the missing angle is 30º
Explanation:
In order to find the answer we need to find out what the angle amount actually is. We can use the equation 180º = 110+ 40 + (8x-18).
Now there are two ways to solve this equation you could solve it by starting with the equation actually is or you can find out the missing angle using another equation.
First Method:
Using 180º = 110+ 40 + (8x-18), you first need to do is to combine like terms such as combining 110, 40, and -18, giving you 132.
Now you have 180 = 132 + 8x.
Then you will have to make sure that 8x is left by itself so do the opposite operation and to keep the equation balanced you do it on both sides giving you 48 = 8x. The only step left to do is to do the opposite operation on both sides which is dividing by 8, giving you 6 = x
Now with that, you replace x, with 6, and go from there.
(8x-18) = (8×6-18) = (48 - 18) = 30.
With that, we are finished with the equation.
However, the other method you could use, which is easier in my opinion, can be found below.
Second Method:
The first thing we do is find out immediately what the missing angle (m) is using the equation 180 = 110 + 40 + m.
You combine like terms 110 and 40, giving 150 and then get,
180 = 150 + m.
You then do the inverse of operations, which is subtracting 150 from both sides and you get 30 = m.
Now that we complete that we start with our other equation which is:
30 = 8x-18. You then do inverse of -18, which adds 18 to both sides giving: 48 = 8x.
Finally doing the inverse operation of multiplying is dividing 8 by both sides giving 6 = x as the correct answer.