He bought 3 small notebooks (3*7=21) and 3 large notebooks (3*10=30)
21+30=51
f(5) means to replace x in the equation with 5 then solve.
f(x) = x^2 +2x
f(5) = 5^2 + 2(5)
f(5) = 25 +10
f(5) = 35
The answer is D)35
The complete factor of the expression
is
correct option is D.
<h3>What is a factorization?</h3>
It is the method to separate the polynomial into parts and the parts will be in multiplication. And the value of the polynomial at this point will be zero.
The expression is
.
To solve the expression properly we have to take common (2x²). Then we have

The factor is
.
More about the factorization link is given below.
brainly.com/question/6810544
D and C because that the answer