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You are here: Experts > Science > Math for Kids > Basic Math > substitution and elimination
Basic Math - substitution and elimination
Expert: Lynn Houston - 10/24/2009
Question
i really need help with substitution and elimination!!pls help me:
1) X+5Y-26=0
3X+2Y=0
SOLVE 1ST EQUATION BY ELIMINATION.
2) 3X+2Y=0
2X-3Y+13=0
SOLVE THE 2ND EQUATION BY SUBSTITUTION PLS.
PLS HELP ME I AM SOOO CONFUSED. PLS HELP ME AS SOON AS U CAN
Answer
SOLVE 1ST EQUATION BY ELIMINATION.
1) X+5Y-26=0
3X+2Y=0
Multiply the first eq by -3
-3X-15Y+78=0
3X+2Y=0 Now add the two equations
-13y + 78 = 0
-13y = -78 divide by -13
y = 6, therefore x = -4
SOLVE THE 2ND EQUATION BY SUBSTITUTION PLS.
2) 3X+2Y=0
2X-3Y+13=0
Solve one equation for x or y
3x = -2y
x = -2/3y substitute the value of x into the second eq.
2(-2/3y) - 3y + 13 = 0
-4/3y - 3y + 13 = o
- 13/3y + 13 = 0
- 13/3y = -13 multiply both sides by -3
13y = 39
y = 3, therefore x = -2
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