Quadratic Equations (Assignment Help)

[love&bullets]

We just finished our Quadratics unit, and we had an assignment to finish up.

I don't understand even how to start the following three questions;

1. Expand and simplify: -7(x-3)(2x+5)- (3x-2)^2

Do I subtract (after I expand) one from the other?

2. Factor completely:

a) -192x^5 + 88x^4 + 60x^3

I took out a common factor, then used quadratic equation, but there was a negative under the square root...and so it doesn't work.

b)
m^4 - n^6
____
9

(Haven't got a clue)

and #3. Determine the points of intersection of y= x^2 +9x + 18 and y= -2x^2 -12x - 9. (Without graphing).


Steps I should take to solving them would be greatly appreciatly.
<3

 

[pka]

Please review and correct your post.
You have typed ‘=’ when I think you mean ‘+”
Please correct everything.
Also, please show what you have done and what you do not understand.

 

[love&amp;bullets]

lol sry, I was typing really fast.

And i havn't really done anything, because I'm confused about how to even start solving them.

 

[happy]

Did you correct everything? -7(x-3)(2x=5)- (3x-2)^2 ???????????????????????? :shock: Triple check your work BEFORE you post it. It's called courtesy.

 

[Unco]

G"day, love&bullets.

We just finished our Quadratics unit, and we had an assignment to finish up.

I don't understand even how to start the following three questions;

1. Expand and simplify: -7(x-3)(2x+5)- (3x-2)^2

Do I subtract (after I expand) one from the other?
Like terms, yep.
2. Factor completely:

a) -192x^5 + 88x^4 + 60x^3

I took out a common factor, then used quadratic equation, but there was a negative under the square root...and so it doesn't work.
It's not an equation so we can't solve it. Once you bring out 4x^3 factorise the quadratic part.

b)
m^4 - n^6
____
9

(Haven't got a clue)
Treat it as a difference of two squares to factorise.

and #3. Determine the points of intersection of y= x^2 +9x + 18 and y= -2x^2 -12x - 9. (Without graphing).
Equate: x^2 +9x + 18 = -2x^2 -12x - 9
Simplify to a quadratic, factorise and solve for x.

 

[love&amp;bullets]

Thank you soooo much.