Is the answer correct:
4x^2+13
2006-11-20 04:49:56 · 15 answers · asked by ME 3 in Science & Mathematics ➔ Mathematics
I see what you did -- you added 3x + x to get 4x, but you knew your answer had to have a square, so you made it 4x². Then you added 8+5 to get 13, for a final answer of 4x̍ + 13.
That's not how to do these. You need to multiply here, not add.
Use a method called FOIL - which stands for First, Outside, Inside, Last. I will demonstrate it for you with your problem:
(3x+8)(x+5)
F - multiply the FIRST terms of each parentheses:
3x * x = 3x²
O - multiply the OUTSIDE terms of each parentheses:
3x * 5 = 15x
I - multiply the INSIDE terms of each parentheses:
8 * x = 8x
L - multiply the LAST terms of each parentheses:
8 * 5 = 40
Now that you've done the FOIL multiplication, you can add up your terms, as follows:
3x² + 15x + 8x + 40
Finally, combine your like terms (the 15x and 8x) to get your final answer:
3x² + 23x + 40
Hope that helped!
~ ♥ ~
2006-11-20 04:57:47 · answer #1 · answered by I ♥ AUG 6 · 1⤊ 0⤋
"Product" is the answer you get when you multiply numbers together. 4x + 13 is the sum (what you get from adding), not the product. To get the product of two binomials (two-part numbers such as 2x + 6), use the FOIL method:
Multiply the FIRST term of each binomial:
3x X x = 3x^2
Then multiply the OUTSIDE numbers
3x X 5 = 15x
Multiply the INSIDE numbers
8 X x = 8x
Now multiply the LAST numbers
8 X 5 = 40
Combine the products from the outside and inside operations to simplify your answer to:
3x^2 + 23x + 40
2006-11-20 04:59:37 · answer #2 · answered by bgdddymtty 3 · 0⤊ 0⤋
3x^2 + 23x + 40
2006-11-20 06:38:32 · answer #3 · answered by ry 1 · 0⤊ 0⤋
Nope!
Do it like a regular multiplication: write it like so, and start from the right, just like long multiplication:
3x + 8
x + 5
--------- right to left:
40
15x
8x
3x^2
---------- add them up
3x^2 + 23x + 40
This works for any length, just like multiplication works for any size numbers. No need to remember little rules or mnemonics.
2006-11-20 04:55:50 · answer #4 · answered by modulo_function 7 · 0⤊ 0⤋
3x^2 + 23x + 40
2006-11-20 04:58:57 · answer #5 · answered by Anonymous · 0⤊ 1⤋
3x^2 + 23x + 40
2006-11-20 04:53:04 · answer #6 · answered by emailandrewt 2 · 0⤊ 1⤋
no that isnt the answer:
{3x+8} {x+5}
3x^2 +15x +8x +40
3x^2 +23 +40
U multiply the first bracket by the contents in the second bracket and get ur answer
2006-11-20 09:59:36 · answer #7 · answered by Anonymous · 1⤊ 0⤋
=3x^2+15x+8x+40
=3x^2+23x+40
2006-11-20 05:48:26 · answer #8 · answered by openpsychy 6 · 0⤊ 0⤋
3x^2+23x+40
2006-11-20 04:57:59 · answer #9 · answered by Nagesh G 1 · 0⤊ 1⤋
3x^2+23x+40
2006-11-20 04:53:03 · answer #10 · answered by r 2 · 0⤊ 1⤋