Question

if (a,15) is a point on the graph of y=x^2+2x, what is a?

Answer 1

Substitute the coordinate given into your equation. Then solve for a

Answer 2

substitute 15?

Answer 3

From (a, 15), we know that y = 15 and x = a. 15=a²+2a

Now solve for a.

Answer 4

since (a, 15) satisfies so put x = a and y = 15
you get
15 = a^2 + 2a
now this is a simple quadratic eq to solve

Answer 5

Can you handle it now?

Answer 6

Yea thank you

Answer 7

I got (-3,5/2)

Answer 8

I got it

Answer 9

None. Find a using quadratic formula. 0 = a² + 2a - 15 Did you do that?

Answer 10

or you can factor it then find a.