2 - b.
3 - a.
I'm not sure about 4. Hope this helps!
(400-300)/300 x 100 = 100/300 x 100 = 33.33% increase
Answer:
A quadratic equation is some thing like
(x+2)^2
or
(x+2)(x+5)
In order to solve them, the most basic method is the FOIL method
F-First
O-Outside
I-Inner
L-Last
So for example
(x+2)^2
Which is basically
(x+2)(x+2)
So the first is the 2 Xs
(x+2)(x+2)
x*x=x^2
The outer is the x and the 2,
(x+2)(x+2)
2*x=2x
Now the Inner which is the 2 and the x
(x+2)(x+2)
2*x=2x
And finally the last which is the 2 and the second 2
(x+2)(x+2)
2*2=4
Now add them all up
X^2+2x+2x+4
Combine like terms
x^2+4x+4
There you have it
Do the same with every other quadratic equation
First you subtract 9x from y and you get 45 - 9x = -y and you don't want negatives so you switch all the signs to get y = -45 + 9x
