SOLUTION: I am working on Algebra, Systems of Equations and Inequalities. I am very confused. The question is SUBSTITUTION Use substitution to solve each system of equations. {{{ x=3y

Algebra ->  Inequalities -> SOLUTION: I am working on Algebra, Systems of Equations and Inequalities. I am very confused. The question is SUBSTITUTION Use substitution to solve each system of equations. {{{ x=3y      Log On


   

Question 853441: I am working on Algebra, Systems of Equations and Inequalities. I am very confused. The question is
SUBSTITUTION
Use substitution to solve each system of equations.
+x=3y+
+2x%2B3y=15+
x=
y=

+x-2y=4+
+3x=6y%2B12+
x=
y=

+x=5y-2+
+2x%2B2y=4+
x=
y=
Found 2 solutions by Alan3354, JulietG:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
Use substitution to solve each system of equations.
+x=3y+
+2x%2B3y=15+
x is solved for in the 1st eqn, so sub for x in the 2nd.
+2%2A3y+%2B+3y=15+
9y+=+15
y+=+5%2F3
-----
x = 3y
x = 5
=================================
+x-2y=4+ --> x = 2y + 4
+3x=6y%2B12+
Same as the 1st one.
========================
+x=5y-2+
+2x%2B2y=4+
Same as #1.
email via the TY note for help or to check your work.

Answer by JulietG(1812) About Me  (Show Source):
You can put this solution on YOUR website!
Let's look at the first one.
x = 3y
2x + 3y = 15
.
To solve this using substitution, take the known value of X from the first equation and put it into the second equation.
.
2x + 3y = 15
2(3y) + 3y = 15 (substituted the 3y in place of the X)
Multiply
6y + 3y = 15
Add
9y = 15
Divide each side by 9
Y = 15%2F9
If y = 12%2F3, then x = 3 * 12%2F3, or 5 [x=3y from the first equation]
.
Use the same method to solve the others. If you need further help, please post questions one at a time.