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#5 to #2

ffx (01/22/2013) []
Look at the first equation : 2x + 9y = 0.
What is the first numbers you'd think that can cancel each other out to make it a perfect 0?
simple watch this: 2x + 9y = 0
*9 *2
18 + 18 = 0
Now if you try it on the 3x + 5y = 17 to confirm:
3(9) + 5(2) = 17
27  10 = 17
17 = 17
What is the first numbers you'd think that can cancel each other out to make it a perfect 0?
simple watch this: 2x + 9y = 0
*9 *2
18 + 18 = 0
Now if you try it on the 3x + 5y = 17 to confirm:
3(9) + 5(2) = 17
27  10 = 17
17 = 17
#10 to #3

anonymous (01/22/2013) []
guessing and checking works in this case because it is easy the real solutions is:
2x + 9y = 0 => 2x = 9y => x = (9/2)y => x = (4.5y)
now sub into other equation:
3(4.5y) + 5y = 17 => (13.5)y + 5y = 17 => 8.5y = 17 => y = (1/2)
now sub y value into original equation:
2x + 9(0.5) = 0 => 2x  4.5 = 0 => 2x = 4.5 => x = 2.25
y = 0.5; x = 2.25
2x + 9y = 0 => 2x = 9y => x = (9/2)y => x = (4.5y)
now sub into other equation:
3(4.5y) + 5y = 17 => (13.5)y + 5y = 17 => 8.5y = 17 => y = (1/2)
now sub y value into original equation:
2x + 9(0.5) = 0 => 2x  4.5 = 0 => 2x = 4.5 => x = 2.25
y = 0.5; x = 2.25