how to solve y= 3cos2x + 5

pls help me

Is that really cos(2x) or do you mean cos^2 x?

I will assume that you really do mean cos(2x). In that case

cos(2x) = cos^2 x - sin^2 x
= 2 cos^2 x -1

y = 6 cos^2x -3 + 5 = 6 cos^2 x - 2
cos^2 x = (y+2)/6
cos x = sqrt[(y+2)/6)]

You can use that to solve for x, if that is what the question is all about.

You cannot solve a single equation for both x and y.

Sure, I can help you solve the equation y = 3cos(2x) + 5.

To solve this equation, we want to find the values of x that make y equal to a certain value.

Step 1: Start by subtracting 5 from both sides of the equation to isolate the cosine term:
y - 5 = 3cos(2x)

Step 2: Divide both sides by 3 to isolate the cosine term:
(y - 5) / 3 = cos(2x)

Step 3: To solve for x, take the inverse cosine (also known as arccos) of both sides:
arccos((y - 5) / 3) = 2x

Step 4: Divide both sides by 2 to isolate x:
x = arccos((y - 5) / 3) / 2

Now you have the equation to find the values of x that satisfy the given equation y = 3cos(2x) + 5.

To find specific values of x, you need to substitute different values of y into the equation above, then calculate the corresponding values of x using a scientific calculator or computer software that can compute inverse cosine (arccos) function.