Posted by ladybug on Sunday, October 28, 2012 at 8:49pm.
if (a,20) is a point on the graph of y=x^2+9x, what is a?

college algebra  Steve, Sunday, October 28, 2012 at 8:56pm
solve for x:
20 = x^2 + 9x
x^2+9x+20 = 0
(x+5)(x+4) = 0
so, a = 4 or 5