Question

Help again and thanks..........

Answer 1

• a = $8
• s = $5

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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Comment on the question

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