9/4x + 7/-5x
2007-04-27 12:57:02 · 7 answers · asked by Unheard 3 in Science & Mathematics ➔ Mathematics
I got 17/20x, but I'm not 100% sure.
2007-04-27 12:57:54 · update #1
You got 1t/20x ?
2007-04-27 13:02:22 · update #2
Thanks for answering
2007-04-27 13:03:40 · update #3
yep, that's what i got too.
2007-04-27 13:00:49 · answer #1 · answered by Rupak C 1 · 0⤊ 1⤋
9 / 4x + 7 / -5x
Since the denominator needs to be the same in both fractions in order to add them, you will have to change them.
Multiplying by 5 / 5 is the same thing as multiplying by 1, right?
So,
9 * 5 / 4x * 5 = 45 / 20x
Multiplying by 4 / 4 is the same as multiplying by 1, so
7 / -5x = 7 * 4 / -5x * 4 = -28 / 20x
Now that they have the same denominator, add them.
45 - 28 / 20x = 17 / 20x
2007-04-27 20:03:49 · answer #2 · answered by the redcuber 6 · 0⤊ 0⤋
Yes, it's 17/(20x).
Note: I prefer to enclose a multi-term denominator in parentheses, to avoid any possible ambiguity. Here's how one gets this result:
9/(4x) - 7/(5x) = [9*5 - 7*4]/(4*5) = [45 - 28]/20 = 17/20.
QED
Live long and prosper.
2007-04-27 20:00:54 · answer #3 · answered by Dr Spock 6 · 0⤊ 0⤋
9/4x + 7/ -5x
lcd is 20x^2
45 + -28= 17/20x
2007-04-27 20:08:33 · answer #4 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋
we need the lcd.
the lcd = 20x
9/4x = 45/20x
7/-5x = -28/20x
45/20x - 28/20x =
17/20x
2007-04-27 20:18:39 · answer #5 · answered by Anonymous · 0⤊ 0⤋
9/4x+7/-5x
=9/4x-7/5x
={9*5-7*4)/20x
=(45-28)/20x
=17/20x
2007-04-27 20:04:47 · answer #6 · answered by alpha 7 · 0⤊ 0⤋
That's right!
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www.simplifymymath.com
2007-04-27 20:01:13 · answer #7 · answered by PCIT411 2 · 0⤊ 1⤋