-5c/8 = 20 what is the value of c

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You said that                    -5c/8  =    20

Multiply each side by  8:  -5c     =  160

Divide each side by  5 :   - c      =    32

Multiply each side by -1 :   c      =  -32 

23,598 because  513 x 40 = ( 500 x 40 ) + ( 10 X 40 ) + ( 3 x 40 ) = 20 000 + 400 + 120 = 20,520 and another partial product is  513 x 6 = ( 500 x 6 ) + ( 10 x 6 ) + ( 3 x 6 ) = 3 000 + 60 + 18 = 3,078. so 20,520 + 3,078 = 23,598