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.
Answer:
i think it is 1/26
Step-by-step explanation:
<span>-4(x-2)-5(y+2)+(-3)(8-6b)
= -4x + 8 - 5y - 10 - 24 + 18b
= -4x -5y + 18b - 26
hope it helps</span>
Answer:
51
Step-by-step explanation:
4x12-3x3+12
48-9+12=51