Question 193704: how to calculate the formular as below :
1). 2X+3Y=21
2). X/2+Y/3=19/6
Pls help me to find out the best way to solve the problem, TQ
Answer by RAY100(1637)   (Show Source):
You can put this solution on YOUR website! remember three ways to solve linear equations, 1) graph, 2) substitution, 3)elimination
on this one let's try elimination
,
1) 2x+3y=21
2) x/2+y/3=19/6
,
to eliminate fractions let's multiply (2) by 6
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2a) 3x +2y =19
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Comparing 1) and 2a), we might multiply, 1) by 3,,and 2a) by 2,, to get common coefficients
'
1) 6x +9y =63
2a) 6x +4y =38
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Now let's subtract 1)-2a)
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5y=25
y=5,,,,,ANSWER
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substitute into 1)
,
2x+3(5)=21
2x=21-15=6
x=3,,,,,,ANSWER
,
checking
1) 2(3)+3(5)=21
6+15=21,,,ok
2) (3)/2 +(5)3 = 19/6
1.5+1.667=3.167
3.167=3.167 ,,,ok
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