Help me with this im stuck please and thanks

Explain how you do each step what term makes it inconsistent y=2x - 4 ?

One integer is 8 times another. if the product is 72, then find the integers

The ivring berlin learning center would like a possible net profit of $650,000 on its new resource manual it sells to schools. the fixed costs for producing the manual are $780,000 and the variable cost per package is $19.85. if the estimated unit sales are 1,250,000 units, what selling price unit should the ivring berlin learning center try?