Kenty,
How about
4x - 5y = 12
x + 10y = 3.
In the elimination method you want to manipulate the equations so that the coefficients of x match or the coefficients of y match. For this pair of equations I see two ways to accomplish this.
- Multiply the second equation by 4. This would result in the term 4x in each equation.
- Multiply the first equation by 2. This would result in the term -10y in the first equation and 10y in the second equation.
Lets do it both ways.
- Multiply the second equation by 4. This results in
4x - 5y = 12
4x + 40y = 12
Subtract the two equations to get
-45y = 0 or y = 0. If you substitute y = 0 into either of the two initial equations you get x = 3. Thus the answer is x = 3, y = 0.
- Multiply the first equation by 2. This results in
8x - 10y = 24
x + 10y = 3
This time add the two equations to get
9x = 27 or x = 27/9 = 3. Now substitution of x = 3 into either of the initial equations gives y = o.
In some systems you may need to manipulate both equations to produce a system where two of the coefficients match.
Try your system and write back if you still need help.
Penny
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