If it’s 30% converted to a decimal it’ll be .30
6)
2(9+10) = 38
2(5+6) = 22
P = 38+22=60 in
14)
9 x 10 = 90
6 x 5 = 30
A = 90+50 = 140 in^2
Hi there!

We are given:
cos(7x)cos(4x) = -1 - sin(7x)sin(4x)
Begin by moving all terms with variables to one side:
cos(7x)cos(4x) + sin(7x)sin(4x) = -1
The corresponding trig identity is cos(A - B). Thus:
cos(7x - 4x) = cos(7x)cos(4x) + sin(7x)sin(4x) = -1
cos(3x) = -1
cos = -1 at π, so:
3x = π
x = π/3
We can also find another solution. Let 3π = -1:
3x = 3π
x = π
Thus, solutions on [0, 2π) are π/3 and π.
Not sure what the question is, but I'm guessing you want to find out the area of the rectangle.
The distance between points P and Q is 4.
The distance between points Q and R is 3.
So the area is 3 * 4 = 12.