if x+3x is 7 more than y+3y then x-y =....
a) o
b) 3/7
c) 4/7
d) 7/3
e) 7/4
I really dont get this... please help...
2007-01-10 13:30:02 · 5 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
the answer is e.
Look at it this way:
x+3x = 7 + (y+3y) which can be 4x=7+4y.
Bring 4y over to the other side for 4x-4y=7
divide by 4 so that x-y=7/4
2007-01-10 13:37:55 · answer #1 · answered by miketor 1 · 0⤊ 0⤋
You know that
x + 3x = y + 3y + 7 (since x+3x is 7 more you need to add 7 to y + 3y to make them equal
4x = 4y + 7
4x - 4y = 7
x - y = 7/4
2007-01-10 21:38:47 · answer #2 · answered by Edgard L 2 · 0⤊ 0⤋
the answer is 7/4 (e)
x+3x=7+y+3y
so 4x=7+4y
So 4x-4y=7
So 4(x-y)=7
=> x-y=7/4
2007-01-10 21:47:35 · answer #3 · answered by Arash J 2 · 0⤊ 0⤋
Simply each side first:
x + 3x = y + 3y + 7
4x = 4y + 7
4x - 4y = 7 <-----bring ys to the other side
x - y = 7/4 <----divide by 4 to get the x-y you are looking for!
So your answer is e)
2007-01-10 21:35:23 · answer #4 · answered by keely_66 3 · 0⤊ 0⤋
x+3x = 7
4x = 7
x = 7/4
Y=3Y = 4y = x - y
5y = x
y = x/5 = 7/20
You must have something wrong with the question.
2007-01-10 21:35:15 · answer #5 · answered by bozo 4 · 0⤊ 1⤋