If (1/4)^(x+y) = 256 and log₄(x-y) = 3, what are the exact values of x and y
1 answer:
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Answer:
- a = $8
- s = $5
Step-by-step explanation:
When the coefficients don't lend themselves to solution by substitution or elimination, then Cramer's Rule can be useful. It tells you the solutions to
- ax +by = c
- dx +ey = f
are ...
- ∆ = bd -ea
- x = (bf -ec)/∆
- y = (cd -fa)/∆
Using that rule here, we find ...
∆ = 5·3 -6·2 = 3
a = (5·54 -6·41)/3 = 5·18 -2·41 = 90 -82 = 8
s = (41·3 -54·2)/3 = 41 -18·2 = 5
This math can be performed in your head, which is the intent of formulating the rule in this way.
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Similarly, if you expect the solutions to be small integers (as here), then graphing is another viable solution method.
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