You plug your 1 into all spots where the variable is T. Then after you’ve done this, you simply simplify the problem. Then after simplifying you should have an equation where you are simply adding and subtracting which will give you the final answer of 2.
X=3T^2-12T+5
X=3(1)^2-12(1)+5
X=(3)^2-12+5
X=9-12+5
X=2
