need some help for math...?

Question

Ok, so, my class has a test soon and my teacher gave us some problems to work on if we wanted to practice or w/e, he also gave us the answers so we could make sure we got it correct... and i dont understand how to do them... here are to examples:

Multiply

1. a^2 - 3a + 4
2a + 3
it should equal to 2a^3 - 3a^2


2. (y + 3)(y + 2)

it should equal to y^2 + 5y +6


(Note: when it says ^ and then a number, it means to the power of, like on the first question, it says a^2 which means a to the second power)

Thanks

Answer 1

I dont really know what you mean with the first question, but here's the explanation to the second:

To multiply two binomials you need to use the FOIL rule, also sometimes known as the double distributive property. The letters in foil stand for the order in which the numbers are multiplied.

First ("first" terms of each binomial are multiplied together)
Outer ("outer" terms multiplied)
Inner ("inner" terms multiplied)
Last ("last" terms multiplied)

The answer is then the sum of the terms obtained from the method. Thus the general form is

(a+b)(c+d) = ac + ad + bc + bd

(y+3)(y+2) = (y x y) + (y x 2) + (3 x y) + (3 x 2)
which equals

y^2 + 5y + 6.

Hope this helps. Good luck and practice practice practice. Remember practice makes perfect :-)

Answer 2

Weird. I have a test on this too. On Friday. Whatever.
I'm going to assume you know the basic rules with polynomials and regular multiplication of integers.

Okay, set up the problems like a multiplication problem such as 12(15).

SIGNS ARE EXTREMELY IMPORTANT!!
1.a^2 - 3a + 4
x 2a + 3
===========
3a^2 - 9a + 12 This is a^2 - 3a + 4 times positive 3.
2a^3 + 6a^2 + 8a " " positive 2a.
============

...Wait a minute....That's not adding up to your answer. Are you sure that's the correct one? Because the method I posted is correct. For the first example, there has got to be a 4 times 3 equals 12 and at the end of the polynomial there should be a something plus 12 because there's nothing in the multplication of 2a that can cancel it out.

Err, hope I helped a little.

Answer 3

The first question i dont get the same answer as your teacher, i get 2a^3 -3a^2 -a+12. The second question i get the answer that your teacher gave.

1. (a^2-3a+4)(2a+3) after you use distributive property you would get 2a^3-6a^2+8a+3a^2-9a+12, you can add like numbers and get 2a^3-3a^2-a+12.

2. (y+3)(y+2) distribute and get y^2+2y+3y+6, add and get y^2+5y+6

good luck.

Answer 4

Really easy...

1. (a^2 - 3a + 4)(2a+3)
(2^3 - 6a^2 + 8a) + (3a^2 - 9a + 12)
2^3 - 3a^2 - a +12 ---- final answer

2. (y + 3)(y + 2)
y^2 + 2y+3y+6
y^2 + 5y + 6

Answer 5

To do the first one, make it look the second one:
(a^2-3a+4)(2a+3)

Then you do the first part in the first parentheses times the first part in the second parentheses. Then times the 1st one itimes the second part in the second parentheses. then you switch:


so.. a^2*2a+a^2*3= 2a^3
and 3a-4*2a+3a*4*3= 3a^2

Answer 6

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Answer 7

First, figure out what A is. Then, you should get your answer.

And for the 2nd one figure out what Y is.

It's simple algebra, you'll cling on soon enough! Good luck on your test!

Answer 8

D.I.Y.