If a and b are acute angles such that sina=4/5 and cosb=12/13, calculate, without using tables: sin(a-b)

There is a spinner with 14 equal areas, numbered 1 through 14. if the spinner is spun one time, what is the probability that the result is a multiple of 2 or a multiple of 5?

3x + 4y = 5 x- 3y = -7 solve by substitution

Given sin∅ = 1/3 and 0 < ∅ < π/2 ; find tan2∅ a. (4√2)/9 b. 9/7 c. (4√2)/7 d.7/9