Let x=number of cds and y=number of dvds

Mathematics

1 answer:

Elis [28]3 years ago

6 0

X + y = 40.....multiply by -4
4x + 6y = 180
-------------------
-4x - 4y = -160 (result of multiplying by -4)
4x + 6y = 180
------------------add
2y = 20
y = 20/2
y = 10 <===

x = 30

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