How do i do highlighted questions with working (only answering one is fine) picture below

Answer of 8:

x= 25°

Step-by-step explanation:

As we can see in the figure given that BAC is a right angled Triangle

Now from simple rules of geometry we know that

Sum of all the angles of a triangle= 180 ⁰  ................. (i)

Now it is given to us that

∠BAC=(2x-5)°

∠ACB=(2x+15)°

and

∠ABC=90°

Now from equation (i) we know that

∠ABC + ∠BAC + ∠ACB =180°  ........... (ii)

putting the values in equation (ii)

(2x-5)° + (2x+15)° + 90° = 180°

2x - 5° + 2x + 15° + 90° =180°

simplifying it will gives

4x + 80° = 180°

4x = 180° - 80°

4x = 100°

cross multiplying gives

()°

which gives us

x= 25°

answer:

c. the third graph