# math

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The cost of thirteen CDs and seven DVDs is \$99.80; and the cost of seven DVDs and twelve CDs is \$84.11.

• math -

want do you need to find?

this problem is not complete

• math -

13c+7d=99.8
12c+7d=84.11
Multiply the 2nd equation by -1
13c+7d=99.8
-12c-7d=-84.11
c=
Plug that back into either original equation to solve for d.

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