X = 12
Use the Pythagorean Theorem.
13^2 = 5^2 + x^2
169 = 25 + x^2
Subtract 25 from both sides.
144 = x^2
Take the square root.
12 = x
That isn’t right I don’t think, if a was 47 then it would be wayyyy bigger of a number. You are finding how 7a-2 is 47. First add 2 to both sides making it 7a=49
7 times what is 49?
That is a
Step-by-step explanation:





Note: I used the identity

for the last step.
PS. I love proving trigonometric identities!