Function rules from equations

Problem

For a given input value x, the function f outputs a value y to satisfy the following equation.
y, plus, 6, equals, 5, left parenthesis, x, minus, 4, right parenthesis
Write a formula for f, left parenthesis, x, right parenthesis in terms of x.
f, left parenthesis, x, right parenthesis, equals
Do 4 problems