Can someone help me please?

see explanation

Step-by-step explanation:

(a)

The sum of the 3 angles in a triangle = 180°

Subtract the sum of the given angles from 180° for B

∠ B = 180° - (90 + 63)° = 180° - 153° = 27°

(b)

Using the sine ratio in the right triangle

sin63° = = = ( multiply both sides by x )

x × sin63° = 15 ( divide both sides by sin63° )

x = ≈ 16.8 ( to 1 dec. place )

(c)

Using the tangent ratio in the right triangle

tan63° = = = ( multiply both sides by y )

y × tan63° = 15 ( divide both sides by tan63° )

y = ≈ 7.6 ( to 1 dec. place )

if you was gonna solve for a, a is a   < -12