can anyone solve x/4 + x/3 = 20?
2009-11-29 1:33 pm
trying to explain this to my son who has this as homework but not sure how to solve this. can anybody explain please. thanks
回答 (9)
2009-11-29 1:41 pm
✔ 最佳答案
x/4 + x/3 = 2012(x/4) + 12(x/3) = 12(20)
3x + 4x = 240
7x = 240
x = 240/7 or 34 2/7
Answer: x = 240/7 or 34 2/7
2009-12-01 7:27 pm
Multiply BOTH sides by 12
3x + 4x = 240
7x = 240
x = 240 / 7
3x + 4x = 240
7x = 240
x = 240 / 7
2009-11-29 9:50 pm
x/4 + x/3 = 20
12(x/4 + x/3) = 12(20)
12x/4 + 12x/3 = 240
3x + 4x = 240
7x = 240
x = 240/7
12(x/4 + x/3) = 12(20)
12x/4 + 12x/3 = 240
3x + 4x = 240
7x = 240
x = 240/7
2009-11-29 9:48 pm
Yes.
2009-11-29 9:45 pm
1) 3x/12 + 4x/12=240/12
2) (3x + 4x)/12=240/12 , =========>
7x=240
x=240/7
------------------------------------------------------------------
CHECK: 240/7 /4 +240/7 /3=20
God bless you.
2) (3x + 4x)/12=240/12 , =========>
7x=240
x=240/7
------------------------------------------------------------------
CHECK: 240/7 /4 +240/7 /3=20
God bless you.
2009-11-29 9:41 pm
Hi,
Multiply every term by the LCD of 12 to eliminate the fractions. Then solve.
x . . x
-- + --- = 20
4 . . 3
3x + 4x = 240
7x = 240
x = 240/7 or 34 2/7 <==ANSWER
I hope that helps!! :-)
Multiply every term by the LCD of 12 to eliminate the fractions. Then solve.
x . . x
-- + --- = 20
4 . . 3
3x + 4x = 240
7x = 240
x = 240/7 or 34 2/7 <==ANSWER
I hope that helps!! :-)
2009-11-29 9:40 pm
Multiply throughout by the LCM of the denominators.
The lowest common multiple of 4 and 3 is 12.
Multiply the WHOLE EQUATION, i.e., EVERY TERM, by 12. Also, note that multiplying the whole equation by any given number does not alter the equation. x + y = 1 is the same as 2x + 2y = 2 (that's (x + y = 1) * 2).
So, 12 * x/4 + 12 * x/3 = 12 * 20
3x + 4x = 240
7x = 240
x = 240/7 = 34.3 (correct to 3 sig. fig.)
I hope that helps. :)
ILoveMaths07.
The lowest common multiple of 4 and 3 is 12.
Multiply the WHOLE EQUATION, i.e., EVERY TERM, by 12. Also, note that multiplying the whole equation by any given number does not alter the equation. x + y = 1 is the same as 2x + 2y = 2 (that's (x + y = 1) * 2).
So, 12 * x/4 + 12 * x/3 = 12 * 20
3x + 4x = 240
7x = 240
x = 240/7 = 34.3 (correct to 3 sig. fig.)
I hope that helps. :)
ILoveMaths07.
2009-11-29 9:39 pm
Multiply the equation by 12 to get
3x+4x = 240
7x=240
x=240/7.
3x+4x = 240
7x=240
x=240/7.
2009-11-29 9:40 pm
cross multiply the bottom of the fractions with the other side of the equals sign
x + x = 20X3X4
2x = 240
x = 120
x + x = 20X3X4
2x = 240
x = 120
收錄日期: 2021-05-01 12:54:09
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20091129053355AA7a0Ba