SAT vs ACT Math - Same Concept, Different Twists

Today I learned that 𝑓(𝑥)
f(x) is just another way of writing y
y, showing the output of a function for a given input. For example, if f(𝑥)=3𝑥+4 f(x)=3x+4,then 𝑓(2)=3(2)+4=10
f(2)=3(2)+4=10. I realized the parentheses mean input, not multiplication, and I need to be careful when substituting expressions like 𝑓(𝑥+1)
f(x+1). This lesson helped me feel more confident solving ACT function problems and reminded me to always follow substitution step by step.