Question 98951: twice one number added to three times another gives 21. find the numbers, if the difference between them is 3. Answer by elima(1433) (Show Source):
You can put this solution on YOUR website! twice one number added to three times another gives 21. find the numbers, if the difference between them is 3.
2x+3y=21
x-y=3
Lets use substitution;
first change the second equation so you have what x equals;
x=3+y
Now plug that into the first equation for x;
2(3+y)+3y=21
6+2y+3y=21
5y=21-6
5y=15
y=3
Now plug your y value into the second equaiton;
x-3=3
x=3+3
x=6
check;
6-3=3
2(6)+3(3)=21
12+9=21
:)
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