Saturday

September 20, 2014

September 20, 2014

Posted by **Lilian** on Monday, March 2, 2009 at 8:51pm.

3x = 4y

x + y = 21

Help please.

- 8th Grade Algebra -
**drwls**, Monday, March 2, 2009 at 11:28pmSubstitute 21 -x for y in the first equation.

3x = 4(21-x)

7x = 84

x = 12

y = 21-x = 9

**Answer this Question**

**Related Questions**

8th grade algebra - need ideas of personal experiences to create a mathematical...

8th grade algebra - need ideas of personal experiences to create a mathematical...

Algebra. - I'm in 8th grade, im in algebra, and this is my question: x=a+b+c...

Alegbra - who ever will help me I do not understand this problem? Solve each ...

8th Grade Math - 5/2t - t = 3 + 3/2t I'm having a hard time to solve this ...

8th grade math - I have no idea how to solve this problem. Can someone help me...

8th grade - I am having trouble with these kinds of problems and I ask my ...

Algebra 1- 8th Grade - How do you solve these types of problems? 1) 3 - n = 32 ...

8th grade - how do you solve ths problem?? 78mi on 3gal (find the unit rate)

8th grade science - an object that weighs 3N displaces 90mL of water which ...