What are the equations for these graphs

If private savings 'v' = 0.75s and total savings 's' equals $4.20 billion, solve for public and private savings.

Jake bakes and sell apple pies. he sells each pie for $5.75 . the materials to make the pies cost $40. the boxes jake puts the pies in cost & 12.50 total. how many pies does jake need to sell to earn a profit of $50

2,10,-50 next two numbers geometric sequence