Answer:
90° + (γ/2)
Step-by-step explanation:
The angles in ΔADB have a sum of 180°, so ...
(A/2) +(B/2) + ∠ADB = 180°
and so do the angles of ΔABC:
A + B + γ = 180°
Dividing this second equation by 2 gives an expression for (A/2) +(B/2) that we can substitute into the first equation:
A/2 +B/2 +γ/2 = 90°
A/2 +B/2 = 90° -γ/2
Putting this in the first equation, we have ...
(90° -γ/2) + ∠ADB = 180°
∠ADB = 90° +γ/2 . . . . . . . . . . add (γ/2 -90°)
Is the x2 supposed to be squared?
Answer:

Step-by-step explanation:
The foil method is used when multiplying 2 binomials. One is (x+9) and another is (3x-4). The steps of FOIL are:
- Multiply the first terms
- Multiply the outer terms
- Multiply the inner terms
- Multiply the last terms
- Combine like terms
Let's do the steps on our problem:
1. multiply x and 3x. So we have x * 3x = 3x^2
2. multiply x and -4. So we have x * -4 = -4x
3. Multiply 9 and 3x. So we have 27x
4. Multiply 9 and -4. So we have -36
Listing the terms, we have: 3x^2 -4x + 27x - 36
We combine like terms and have: 3x^2 + 23x - 36
That's our answer.