X + 3x = 12
(Or 4x=12)
the first x is the number of girls then the second x is the girls times 3, which is how many boys there are.
Option A

<em><u>Solution:</u></em>
Given that we have to rewrite with only sin x and cos x
Given is cos 3x

We know that,

Therefore,
---- eqn 1
We know that,


Substituting these values in eqn 1
-------- eqn 2
We know that,

Applying this in above eqn 2, we get



Therefore,

Option A is correct
Answer:
(x+9)^2 + (y+1)^2 = 100
Step-by-step explanation:
Since the question says diameter, we know the boundary in a circle. Therefore, we just need to find the center and radius.
The center is the midpoint of the two endpoints on a diameter.
Here, it is (-9, -1).
Therefore, the left part of the equation is (x- -9)^2 + (y - -1)^2 = (x+9)^2 + (y+1)^2.
The radius: sqrt(8^2 + 6^2) = 10
So the equation is (x+9)^2 + (y+1)^2 = 100
Answer:
E. he multiplied 9 and 0.7 incorrectly.
Step-by-step explanation: