Please help if you know trig, will give brainliest! Thank you!

tan²(α) (2 cos²(α) + sin²(α) - 1)

Recall that sin²(α) + cos²(α) = 1 for all α. Then sin²(α) - 1 = -cos²(α) :

tan²(α) (2 cos²(α) - cos²(α))

tan²(α) cos²(α)

Rewrite tan(α) = sin(α) / cos(α) :

(sin(α) / cos(α))² cos²(α)

(sin²(α) / cos²(α)) cos²(α)

Cancel the factors of cos²(α) :

sin²(α)

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.