Answer:
Step-by-step explanation:
Angle sum property of triangle: Sum of all the angles of a triangle is 180
Alternate interior angles: When two parallel lines are intersected by a transversal, the pair of angles on the inner side of each of these lines but on the opposite side of the transversal are called alternate interior angles
In ΔABC,
∠1 + 90 + 38 = 180 {angle sum property of triangle}
∠1 + 128 = 180
∠1 = 180 - 128

AB // CD and AC is transversal.
{Alternate interior angles are equal}
In ΔACD,
∠2 + ∠3 + 63 = 180 {angle sum property of triangle}
∠2 + 38 +63 = 180
∠2 + 101 =180
∠2 = 180 - 101

I would solve it for B, but that's just what I think. So you would do -12 time -2 which is 24, then subtract 24 from both sides so that you would get B=-31
If u separate these into 2 triangles then they will become 90 degree triangles so angle a=angle c.
X^2 + 8x + 7= 0
(X+7)(X+1)
X=-1,-7
-5
a^2-25=0
a^2=25
take the square root of both sides
a=5, and -5