Idon't get this one too can someone explain it

15ab

Step-by-step explanation:

When you multiply out the square (p+q)^2, you get the trinomial ...

(p +q)^2 = p^2 + 2pq + q^2

Your binomial is (3a+2.5b), so you have ...

p = 3a

q = 2.5b

and the trinomial you get when you multiply it out is ...

(3a)^2 + 2(3a)(2.5b) + (2.5b)^2

= 9a^2 + 15ab + 6.25b^2

The first and last of these terms are shown on the right side of the given expression, so to finish out the identity, you need to replace * with 15ab.

guess at question:

a vertical line intersects the graph of g(x,y) = 0 at two points. what conclusion follows about the function f(x) implicitly defined by g(x,f(x)) = 0?

the domain of f(x) cannot include the x coordinate of any such vertical line.

informally, f(x) is not a function, and

g(x,y)=0 cannot be solved for y uniquely.

the relation r = {(x,y) such that g(x,y) = 0} is a function if

for all (a,b) ∊ r and (c,d) ∊ r, a=c implies b=d.

step-by-step explanation: