Answer:
a=15
Step-by-step explanation:
By pythagoras' theorem
25²=20²+a²
625=400+a² group like terms
a²=625-400
a²=225

therefore a=15
Actually you can't solve this. There is no solutions.
Answer: Simplify 8/10 which is 4/5.
Step-by-step explanation:
Answer:

Step-by-step explanation:
Suppose h is the inverse of f then
f(x) = y ⇔ h(y) = x
f(x) = y ⇔ 4x = y ⇔ x = y/4
and since x = h(y) then h(y) = y/4
then we can write :

______________________
:)
Multiply top equation by -2, then add equations so b drops out....solve for a...plug in a to get b