It has a minimum value at x = 3 and f(x) = 4
Vertex form is
f(x) = a(x - 3)^2 + 4 where a is some constant to be found
From the graph when x = 5 f(x) = 15, so
15 = a * 2^2 + 4
a = 15-4/4 = 11/4
so our equation is f(x) = 11/4(x - 3)^2 + 4
Multiply the sale price by the commission rate:
550,000 x 0.06 = 33,000
He earned $33,000.00
If the polynomial is of the form x^2+bx+c (ie., no factor in front of the x^2!!) then you can look for numbers that add up to b and multiply to c.
So in this case: what two numbers, when added, give -2 and when multiplied, give 1? A little trial and error gives you -1 and -1.
So the factorization is (x-1)(x-1). This is zero for x=1. There is only one zero.
