Answer:
6xy - 8x + 5y - 4z
Step-by-step explanation:
6xy - 20y + 7z - 8x + 25y - 11z
Group the ones with the variable first to make an equation:
6xy - 8x - 20y + 25y + 7z - 11z
Solve the equation
6xy - 8x +5y - 4z
F(1)=4(1+1+7)-2(1)+8-4
f(1)=36+2
f(1)=38
f(2)=4(2+2+7)-2(2)+8-4
f(2)=44
5 19 6 -18
-3
-15 -12 18
5 4 -6 0
Therefore, the width is 5x^2 + 4x - 6
1 file + 3 pens = $32.85 --------------- (1)
2 files + 8 pens = $83.50 ----------------(2)
(1) x 2 :
2 files + 6 pens = $65.70 ----------------(1a)
(2) - (1a) :
2 pens = $17.80
1 pen = $8.90
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Answer: One pen costs $8.90.
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