Step-by-step explanation:
See whenever we have two variables like x and y.
And also we have given two equations in terms of x and y.
Example: ax + by = p and cx + dy = q
In order to get the solution, we need to find the value of x and y using the given two equations.
So here what we can do is:
Consider any one equation and get x or y from that equation.
i.e consider ax + by = p or x = 
Now plug value of x (or y) from the equation you have considered into the another equation.
i.e c(
)+dy = q
Now solve this equation to get y (or x).
and after that we can find the other variable.
Answer:
1. 20
2. 23
3. 6
Step-by-step explanation:
We have that:
f(x) = 2x
g(x) = x² + 1
f(g(x)) is the composite function of f and g. So
f(g(x)) = f(x²-1) = 2(x²+1) = 2x² + 2
1. f(g(3))
f(g(x)) = 2x² - 2 = 2(3)² + 2 = 18 + 2 = 20
2. f(3)+g(4)
f(3) = 2(3) = 6
g(4) = 4² + 1 = 17
f(3) + g(4) = 6 + 17 = 23
3. f(5) - 2g(1)
f(5) = 2(5) = 10
g(1) = (1)² + 1 = 2
f(5) - 2g(1) = 10 - 2*2 = 10 - 4 = 6