Question 173957
PLEASE EXPLAIN! 
0.05x+0.25y=66 
0.15x+0.05y=72
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To use elimination (and then substitution) multiply one or both eqns to get the same coeffs for one of the variables.
In these 2, multiplying the 1st eqn by 3 will give the same coeffs for x
0.05x+0.25y=66 
0.15x+0.75y=198  eqn1 times 3
0.15x+0.05y=72  Then subtract 2 from 1
0.0x+ 0.70y=126
7y = 1260
y = 180
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Sub for y into either eqn
0.05x + 0.25*180 = 66
5x + 4500 = 6600
5x = 2100
x = 420