okay so can you tell me if this is right, if not please show me the error.
(6d+3a)-(4d-7a)
6d+3a+-4d+-7a
=2d+-4a
And could you help me with these...
#1. (4a-3b-c)-(4b-7)+(9a+5)
#2. (7y-3)+(6y+2)-(3y-7)
2006-09-14 14:11:25 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
(6d+3a)-(4d-7a)
=6d+3a-4d+7a
=2d+10a
2006-09-14 14:15:57 · answer #1 · answered by joe 1 · 0⤊ 0⤋
The first set is wrong. When you see a minus sign you subtract. When you subtract a negative number (with a minus sign of its own) you are really adding that number (taking away less).
That means your third line should be 6d + 3a -4d +7a
You then combine for 6d-4d +7a + 3a which combines to 2d+10a
You were almost all correct except for the confusion with the minus sign.
Do the same for the other two and your homework will be complete and correct.
2006-09-14 21:20:04 · answer #2 · answered by Rich Z 7 · 0⤊ 0⤋
(6d + 3a) - (4d - 7a)
6d + 3a - 4d + 7a
(6 - 4)d + (3 + 7)a
2d + 10a
---------------------------------
1.)
(4a - 3b - c) - (4b - 7) + (9a + 5)
4a - 3b - c - 4b + 7 + 9a + 5
(4 + 9)a + (-3 - 4)b - c + 5
13a + (-3 + (-4))b - c + 5
13a - 7b - c + 5
---------------------------
2.)
(7y - 3) + (6y + 2) - (3y - 7)
7y - 3 + 6y + 2 - 3y + 7
(7 + 6 - 3)y + (-3 + 2 + 7)
(13 - 3)y + (-1 + 7)
10y + 6
2006-09-15 00:40:03 · answer #3 · answered by Sherman81 6 · 0⤊ 0⤋
You're first answer is wrong. You forgot to change the sign of
-7a. Remember -(-7a) = +7a.
(6d + 3a) - (4d - 7a) =
6d + 3a - 4d + 7a =
2d + 10a
Watch your signs and the others are easy!
2006-09-14 21:18:43 · answer #4 · answered by Jack D 2 · 0⤊ 0⤋
You're half right.
(6d+3a)-(4d-7a)=
6d -4d+3a -(-7a)=
2d +10a
since -(-7a) turns into +7a
You can figure out the other ones. Group them by letters, but watch your signs.
2006-09-14 21:17:09 · answer #5 · answered by siamcatp 4 · 0⤊ 0⤋
(6d+3a)-(4d-7a)
Keep in mind when 2 opposite signs are multiplied the NEGATIVE sign wins; And when 2 similar signs are multiplied the POSITIVE sign wins
Ex: (-) x (-) = +Ve
(-) x (+)= -Ve
Hence for (6d+3a)-(4d-7a)
After omitting parentheses:
=6d+3a-4d+7a (by adding the "d's and the "a's) you get after
putting them alphabetically in order
3a+7a+6d-4d
=10a+2d (Final Answer)
2006-09-14 22:14:38 · answer #6 · answered by Shufimafi 1 · 0⤊ 0⤋
The sign of the term 7a in your second line is not correct. The - outside the parenthesis multiplies each term inside. You got the -4d allright, but - times -7d is +7d.
2006-09-14 21:19:11 · answer #7 · answered by gp4rts 7 · 0⤊ 0⤋
well the =2d+-4a should be written as =10a+2d
the minus sign changes all the signs after it
1.
combine like terms
4a+9a=13a
-3b+4b=b
-c= -c
-7+5=-2
answer:
13a+b-c-2
2. combine like terms
7y+6y-3y=13y
3+2+7=12
answer:
13y+12
2006-09-14 21:17:21 · answer #8 · answered by Roshni 3 · 0⤊ 0⤋
it would be +6d +3a -4d -(-7a) so you would add the 7a
= 2d + 10a
2006-09-14 21:17:19 · answer #9 · answered by Samantha O 2 · 0⤊ 0⤋
there are many web sites that will help you with that. if you do the work then it will mean more to you than if you have some one do it for you. Believe me I know I too just started math after 30 Years out of school
2006-09-14 21:22:39 · answer #10 · answered by ? 1 · 0⤊ 0⤋