<span>f(x) = ax2+bx+c, is quadratic equation
</span><span>function opening downward if the a<0,
</span><span>kf(x) = -x², a= -1<0
so the answer is </span><span>B.kf(x) </span><span>
</span>
The area of the shaded region will be the area of the rectangle minus the area of the white square inside of it:
((x+10)(2x+5)) - ((x+1)(x+1))
First, FOIL both of the areas separately:
(2x^2 + 5x + 20x + 50) - (x^2 + x + x + 1)
Simplify within the parentheses by adding like terms:
(2x^2 + 25x + 50) - (x^2 + 2x + 1)
Now, subtract one equation from the other:
2x^2 + 25x + 50
-x^2 - 2x - 1
= x^2 + 23x + 49
This will be the equation for the area.
