I can get the numbers, but when it comes to - or +, I get all confused! Does anyone know of an easy way to keep it straight?
2006-08-12 05:50:43 · 19 answers · asked by bobbysgirlmeri 2 in Science & Mathematics ➔ Mathematics
Use the distributive property and be very careful about keeping the numbers. Also remember if there is no number in front of the term then there is an "implied" +1 or -1 don't leave that out. So here goes for the problem that you mentioned.
-3xy -3x +xy -4x
-3xy + 1xy -3x -4x (just moving the terms closer to their matching term)
(-3 + 1)xy + (-3 -4)x ( watch those signs and whether you add or subtract)
(-2)xy + (-7)x ( combine constants)
-2xy -7x ( remove parentasis)
Hope this helps - don't skip steps until you gain more experience will help prevent mistakes.
2006-08-12 06:01:26 · answer #1 · answered by rscanner 6 · 1⤊ 0⤋
Here are a few pointers:
x - y = x + (-y)
a + b = b + a
If we "mix" these two, we get:
-y + x = (-y) + x = x - y
So all you do if you see a negative sign before a number is put it somewhere else in the equation so that you have subtraction.
Doing so on you problem:
-3xy -3x +xy -4x = xy - 3xy -3x -4x
Now, if you have 2 numbers with a negative sign, you can look at the next line:
-x -y = - (x+y)
I think you know how to group like terms, so I'll skip to the end:
-3xy -3x +xy -4x
= xy - 3xy -3x -4x
= (xy - 3xy) - (3x +4x)
You can do the rest, I hope.
2006-08-12 07:23:07 · answer #2 · answered by dennis_d_wurm 4 · 0⤊ 0⤋
Here's a simple rule...don't mess with minus, play with positive. If you can play around with the positives and let the minuses sort themselves out, it should work. Observe:
-3xy - 3x + xy - 4x
=x(-3y -3 + y - 4)
=x(-3y + y - 4 -3)
=x(-2y - 7)
=-2xy - 7x
2006-08-12 10:45:23 · answer #3 · answered by hackmaster_sk 3 · 0⤊ 0⤋
You can combine like terms (defined as terms with the same variables and exponents)
-3xy and +xy are like terms and would be equal to -2xy
-3x and -4x are like terms and would equal -7x
Combining the two results, the answer is -2xy - 7x
2006-08-12 06:09:00 · answer #4 · answered by AskOnlyMe 3 · 0⤊ 0⤋
-3xy - 3x + xy - 4x Original Problem
-3xy + (-3x) + xy + (-4x) Change the operations to addition
-3xy + xy + (-3x) + (-4x) Use the Commutative Property of Addition
-2xy + (-7x) Simplify
Final Answer : -2xy - 7x
2006-08-12 06:02:46 · answer #5 · answered by xinnybuxlrie 5 · 0⤊ 0⤋
-2xy-7x
The plus or minus applies to the sign IN FRONT OF the number So you add xy to a -3xy and subtract a 4x from -3x
2006-08-12 05:53:50 · answer #6 · answered by DonSoze 5 · 2⤊ 0⤋
add like terms. Add the coefficients that have the same x-y terms.
-3xy -3x +xy -4x becomes
-3xy +xy -3x -4x becomes
(-3xy +xy) +(-3x -4x) becomes
(-2xy) + (-7x)
-2xy -7x
So it becomes -2xy -7x
I don't know if this needs to be factored, but if it does
-x*(2y +7)
2006-08-12 06:08:47 · answer #7 · answered by PC_Load_Letter 4 · 0⤊ 0⤋
add one positive to three negatives
-3xy + xy = -2xy
add negative three and negative four (the invisible plus sign is understood to be there)
-3x -4x = -7x
so the answer would be -2xy-7x or -7x-2xy.
2006-08-12 09:09:20 · answer #8 · answered by ronw 4 · 0⤊ 0⤋
-3xy - 3x + xy - 4x
(-3 + 1)xy + (-3 - 4)x
-2xy + (-3 + (-4))x
-2xy - 7x or -x(2y + 7)
2006-08-12 07:25:13 · answer #9 · answered by Sherman81 6 · 0⤊ 0⤋
-3xy -3x +xy - 4x
Put like terms in one bracket i.e.
(-3xy +xy) +( -3x -4x)
Then simplify them
(-2xy) + (-7x)
Open the brackets
-2xy - 7x
2006-08-12 06:35:13 · answer #10 · answered by Amar Soni 7 · 0⤊ 0⤋