3(4)(5) = 12(5) = 3(20) = 60
no, only multiply 1 of them by 3. this is associative property of multiplication, not distributive property.
I'd multiply out the polynomials, then multiply by 3:
3(x - y + z)(x + y + z) =
3(x² + xy + xz - xy - y² - yz + xz + yz + z²) =
3(x² - y² + z² + 2xz) =
3x² - 3y² + 3z² + 6xz
you forgot to type the 3 in front of z²
2007-05-31 10:57:45
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answer #1
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answered by Philo 7
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For the question 3(x - y + z)(x + y + z), here's what you do:
First, you use the distributive property in the parenthesis: We will begin with the variable x in the first parenthesis:
x * x = x^2
x * y = xy
x * z = xz
Next, we multiply -y:
-y * x = -xy
-y * y = -y^2
-y * z = -yz
Then, we multiply z:
z * x = xz
z * y = yz
z * z = z^2
Now, you organize them all together:
x^2 + xy + xz + -xy - y^2 - yz + xz + yz + z^2
Then, we will combine like terms:
x^2 - y^2 + z^2 + xy - xy + xz + xz - yz +yz
We are now left with the following:
x^2 - y^2 + z^2 +2xz
We cancelled out xy and yz.
Now, we have 3 (x^2 - y^2 + z^2 + 2xz)
We then multiply each one by 3
3 * x^2 = 3x^2
3 * y^2 = -3y^2
3 * z^2 = 3z^2
3 * 2xz = 6xz
Now we have the answer: 3x^2 + 6xz - 3y^2 + z^2
That's all the steps required to derive the answer. Good luck! :-)
2007-05-31 18:15:18
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answer #2
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answered by Maria Gallercia 4
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You have to multiply out the brackets first!
Step 1 - Multiply out the brackets:
3 ( x - y + z )( x + y + z )
= 3 ( x^2 + xy +xz - yx - y^2 - yz + zx +zy + z^2 )
Step 2 - Tidy up the numbers in the bracket:
3 ( x^2 + 2xz - y^2 + z^2 )
Step 3 - Multiply the numbers in the bracket by the 3 and that gives your answer:
3x^2 + 6xz - 3y^2 + z^2
Hope that explains it!
2007-05-31 18:02:06
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answer #3
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answered by Bright Spark 2
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ever done foiling? multiply (x-y+z) times (x+y+z). you would get:
x^2 + xy+ xz + -y^2 + -yx + -yz + zx + zy + z^2
ever canceled things out? xy and -yx cancel, and so do -yz and zy. so taking out the canceled things means:
x^2 + xz + zx -y^2 + z^2
now here's where the 3 comes in. multiply everything by 3
3(x^2 + xz + zx + y^2 + z^2) becomes 3x^2 + 3xz + 3zx + -3y^2 + 3z^2
3xz + 3zx = 6xz (order with the letters doesnt matter. each letter matches up with each letter. that's why the other things cancelled.)
3x^2 + 6xz + -3y^2 + 3z^2
2007-05-31 18:00:41
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answer #4
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answered by dance_this_world_away 3
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Multiplication is commutative, so work the brackets first.
3(x -y + z)(x + y +z)
= 3 * (x^2 +` xy + xz - yx - y^2 - yz + zx + zy + z^2)
Now bring like terms together ... (Note xy is the same as yx)...
= 3 * (x^2 +` xy - yx +xz + zx - yz + zy - y^2 + z^2)
= 3 * (x^2 + 2xz - y^2 + z^2)
= 3x^2 + 6xz - 3y^2 + 3z^2
2007-06-01 09:40:19
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answer #5
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answered by Rush 1
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Why not use the difference of two squares?
3(x -y + z)(x + y +z)
= 3[(x+z)^2-y^2]
= 3[x^2+2xz+z^2-y^2]
= 3x^2 +6xz -3y^2 +6z^2.
2007-05-31 18:03:46
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answer #6
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answered by sahsjing 7
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Expand & simplify the expression.
FirsT: combine the 1st two terms - use the Distribution Method.
3(x -y + z) = 3(x)+3(-y)+3(z) = = 3x-3y+3z
you have... (3x-3y+3z)(x+y+z)
Sec: combine the last two terms - use the Foil Method.
(3x)(x)+(3x)(y)+(3x)(z)+(-3y)(x)+(-3y)(y)+(-3y)(z)+(3z)(x)+(3z)(y)+(3z)(z)
= 3x^2+3xy+3xz-3xy-3y^2-3yz+3xz+3yz+3z^2
Third: combine "like" terms.
= 3x^2+3xy-3xy+3xz+3xz-3y^2-3yz+3yz+3z^2
= 3x^2 + 6xz - 3y^2 + 3z^2
and the expression has to be placed in alpha descending order...which is, 3x^2 - 3y^2 + 3x^2 + 6xz
P.S. the result is not 3x^2 +6xz -3y^2 +z^2
2007-05-31 18:24:24
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answer #7
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answered by ♪♥Annie♥♪ 6
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3(x-y+z)(x+y+z)
Multiply the two trinomials first
3(x^2+xy+xz-xy-y^2-yz+xz+yz+z^3)
Simplify
3(x^2+2xz-y^2+z^3)
Distribute the 3
3x^2+6xz-3y^2+3z^2
2007-05-31 17:54:20
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answer #8
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answered by hawkeye3772 4
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No, you can multiply the three by either quantity, but only 1 of the quantities.
(3x-3y+3z)(x+y+z)
3x^2+3xy+3xz-3xy-3y^2-3yz+3xz+3yz+3z^2
3x^2+3xz-3y^2+3z^2
2007-05-31 17:53:41
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answer #9
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answered by Anonymous
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You have 3 a b. First multiply a by b and then, by 3
Ilusión
2007-05-31 18:05:26
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answer #10
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answered by Ilusion 4
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