hi does anybody know the answer to this math(substitution) problem, x=3y
2x+3y=15 if any body know please tell me? THANKS
2006-07-09 05:42:46 · 17 answers · asked by ISABEL 1 in Science & Mathematics ➔ Mathematics
If x = 3y, then you can substitute the 2x in your problem with 6y.
Then add 6y + 3y and you get 9y.
Divide both sides (9y=15) by nine and you get y=15/9 or y=1.6666666666666666667.
Since you now know what y equals you can solve for x. If x=3y then x= 3*1.66666666666667 or x=5.
2006-07-09 05:49:21 · answer #1 · answered by Don K 3 · 0⤊ 0⤋
Since x=3y, the second formula can be rewritten as 2x + x = 15, or 3x = 15. Divide both sides by 3, and that results in x = 5. Substituting 5 for "x" in the second formula gives 2*5+3y = 15 or 10 + 3y = 15. Subtracting 10 from each side results in 3y = 5. So dividing each side by 3 leaves y = 1 2/3
2006-07-09 06:24:48 · answer #2 · answered by June Bug 1 · 0⤊ 0⤋
This is not very hard. Due to the fact that x=3y. We can simply replace 3y with x.
So, 2x+x=15
3x=15
x= 5
2006-07-09 05:46:04 · answer #3 · answered by Science_Guy 4 · 0⤊ 0⤋
it is vry simple.See..wen there r 2 diff variables in a question substitute one for other.such equations r called substitutions.In the quest above we can write 3y in place of x and then the whole eq. will b reduced in the terms of y....now its easy to solve it.
2x+3y=15(eq)
2(3y)+3y=15
6y+3y=15
9y=15 or y=15/9=5/3
putting y=5/3 in eq
2x+3*5/3=15
2x=15-5
2x=10 or x=10/2=5
ans.x=5,y=5/3
2006-07-09 06:20:15 · answer #4 · answered by katie 1 · 0⤊ 0⤋
simply substitute the value x=3y in this equation
2x+3y=15
2*3y + 3y = 15
6y +3y=15
9y = 15
y = 15/9
2006-07-09 06:08:09 · answer #5 · answered by cutiepie_4ever 2 · 0⤊ 0⤋
2*3y+3y=15
6y + 3y = 15
9y=15
y=15/9 or 5/3
2006-07-09 05:53:59 · answer #6 · answered by Anonymous · 0⤊ 0⤋
sounds lik x = 5 cuz x+x=10)+3y=x) so thats x+x+x=15
or 3 times five=15
2006-07-09 05:53:24 · answer #7 · answered by freikeygee@sbcglobal.net 2 · 0⤊ 0⤋
x = 2y
2x + 3y = 15
substitute : just replace x with 2y. this is allowed because x=2y
you get :
2y + 3y = 15
or 5y = 15
now y = 15/5 ; ( divide both sides by 5 , 5y/5 = y )
and you read y = 15/5 = 3 .
Now for the x.
x = 2y , y = 3 thus x = 2 * 3 = 6
2006-07-09 05:51:43 · answer #8 · answered by gjmb1960 7 · 0⤊ 0⤋
Well, 2 x 6 + 3 x1=15, (x being 6 and Y being 1) but 6 does not equal 3 x 1 so, partly there.
2006-07-09 05:56:20 · answer #9 · answered by Anonymous · 0⤊ 0⤋
Well!
if x=3y so we can have "6y" instead of "2x". (2 multiply by 3 =6)
so our problem is this now : 6y+3y=15
so:9y=15
To calculate the amount of y, we have to devide 15 into 9.
Then our answer is available: 1.666666667 (y=1.666666667)
& for x: 2x+x=15
so : 3x=15
so x=15/3
x=5
2006-07-09 05:50:57 · answer #10 · answered by Anonymous · 0⤊ 0⤋