Insect 4 arithmetic means between -12 and 13​

In a sale there is 25% of all prices a chair costs £45 in sale how much was it before the sale

Urgentwhat is the area of the figure?

There is a linear relationship between a salesperson sales and her weekly income.if her sales are $200 her income is $500 and if her sales are 1,200 her income is $600.what is the relationship between sales and income