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:
[tex]y=-x-30+180[/tex] which then becomes [tex]y = -x+150[/tex].
Also since the inside sum of angles in a traingle is equal to 180°, this can be written as
[tex]180 = (x-40) +(x-30)+y[/tex]
if we replace y with the equation we get
[tex]180=(x-40)+(x-30) + (-x+150)[/tex]
which can be simplified to
[tex]180=x+80[/tex] because 2x-x = x and -70+150 = 80
If we rearrange to solve for x, we get:
[tex]x = 180-80[/tex] ⇒ [tex]x=100[/tex]
We can verify this by putting the value of x in both equation:
[tex]y = -100+150 = 50[/tex] angle at k
[tex]100-40=60[/tex] angle at j
[tex]100-30=70[/tex] angle at l
[tex]50+60+70=180[/tex] this match the rules of the sum of interior angle always equal 180°
