Answer:
first one is simnple cross multiply and divide
12*7=4x
84=4x
x=21
2nd same process but more steps
7x=5(x+8)
7x=5x+40
7x-5x=40
2x=40
x=20
Step-by-step explanation:
First evaluate

what angles in domain of [-pi/2, pi/2] make sin = 0

Now we can evaluate the cos function:
The three numbers have no prime divisors in common:

So, the least common multiple is the product of the numbers:

Answer:
x=5
Step-by-step explanation:
h (x) = 3
We want the x values where y =3
The values are x = -7 and x=5
(4x+1)(x+6).
Is this what you're looking for.