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

if we replace y with the equation we get

which can be simplified to
because 2x-x = x and -70+150 = 80
If we rearrange to solve for x, we get:
⇒ 
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°