Answer:
Step-by-step explanation:
Let 
Subbing in:

a = 9, b = -2, c = -7
The product of a and c is the aboslute value of -63, so a*c = 63. We need 2 factors of 63 that will add to give us -2. The factors of 63 are {1, 63}, (3, 21}, {7, 9}. It looks like the combination of -9 and +7 will work because -9 + 7 = -2. Plug in accordingly:

Group together in groups of 2:

Now factor out what's common within each set of parenthesis:

We know this combination "works" because the terms inside the parenthesis are identical. We can now factor those out and what's left goes together in another set of parenthesis:

Remember that 
so we sub back in and continue to factor. This was originally a fourth degree polynomial; that means we have 4 solutions.

The first two solutions are found withing the first set of parenthesis and the second two are found in other set of parenthesis. Factoring
gives us that x = 1 and -1. The other set is a bit more tricky. If
then
and

You cannot take the square root of a negative number without allowing for the imaginary component, i, so we do that:
±
which will simplify down to
±
Those are the 4 solutions to the quartic equation.
m∠AOC = m∠AOB + m∠BOC
We have m∠AOC = 19°, m∠AOB = 4x - 15 and m∠BOC = 2x + 10. Substitute:
19 = (4x - 15) + (2x + 10)
19 = (4x + 2x) + (-15 + 10)
19 = 6x - 5 <em>add 5 to both sides</em>
24 = 6x <em>divide both sides by 6</em>
4 = x
m∠BOC = 2x + 10 → m∠BOC = 2(4) + 10 = 8 + 10 = 18
m∠AOB = 4x - 15 → m∠AOB = 4(4) - 15 = 16 - 15 = 1
<h3>Answer: c. m∠BOC = 18°, m∠AOB = 1°</h3>
418.93 which is answer choice b
Answer:
A
Step-by-step explanation:
23 x 2 = 46
What type of math is this?