Respuesta :

Answer:

Step-by-step explanation:

(a+b)²=a²+2ab+b²

9x²+30x+ca

=(3x)²+2×3x×5+c

=(3x)²+2×3x×5+5²-5²+c

=(3x+5)²-25+c

it is a perfect square if -25+c=0

or c=25

Answer:

It is a vertical line

Step-by-step explanation:

A line with only x = 2 shows that the y values are countless.  Y would go from 0 to infinity in either direction.

A horizontal line would have several x values and only 1 y value.

It can't pass through 0,2 since x =2 not 0

It also can't pass through the origin of 0,0 since it has only an x value.