Answer:100
Step-by-step explanation:
The question confuses you since there is no extra variable to help you which is you have to create it yourself.
Let's create a variable called 'y' and make it the empty angle inside the triangle and next to x + 30. Since at K it will always equal to 180° because x+30 + y = 180°, we can rearrange to make y alone which would be become:
which then becomes
.
Also since the inside sum of angles in a traingle is equal to 180°, this can be written as
![180 = (x-40) +(x-30)+y](https://tex.z-dn.net/?f=180%20%3D%20%28x-40%29%20%2B%28x-30%29%2By)
if we replace y with the equation we get
![180=(x-40)+(x-30) + (-x+150)](https://tex.z-dn.net/?f=180%3D%28x-40%29%2B%28x-30%29%20%2B%20%28-x%2B150%29)
which can be simplified to
because 2x-x = x and -70+150 = 80
If we rearrange to solve for x, we get:
⇒ ![x=100](https://tex.z-dn.net/?f=x%3D100)
We can verify this by putting the value of x in both equation:
angle at k
angle at j
angle at l
this match the rules of the sum of interior angle always equal 180°