Please help me im so confused

1) in triangle the, what is the measure of angle t (in degrees)? 2) in triangle bat, the measure of angle b is 66∘, and the measure of angle t is 77∘.what is the measure of the exterior angle at a (in degrees)?

X+ y = 5 ; x - y =3 solve using linear combination

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?