Answer:

Step-by-step explanation:
The given trigonometric equation is
.
We can either use the Pythagorean identity or the right angle triangle to solve for
.
According to the Pythagorean identity,

Recall that, the cosine function is an even function, therefore

.
We substitute this value in to the above Pythagorean identity to get;






But we were given that,
, so we choose the negative value.

The correct answer is B
Answer:
0.40x = 320
Step-by-step explanation:
40 = percent, 320 = part. Write the percent as a decimal and multiply by the whole.
Answer:
look at the picture i have sent
Answer:
Step-by-step explanation:
1. 3x2 + 5x - 4 + 6x2 - x + 7
= combining like terms
= 9x2 + 4x + 3
2. 2y2 - 3y + 6 + y2 - 5y - 1 + (-4) + 2y2 - 2y
= 5y2 - 10y + 1
3. 2x2y - 3xy2 + x2y - 4x2y - 2xy2
= - x2y - 5xy2
4. x2 - y2 + 2x2 - 3xy + 4y2 + 3y2 - 5xy - x2
= 2x2 - 8xy + 6y2