Explain how to compare 0.7 and 1/2.

Amerchant has coffee worth $60 a pound that she wishes to mix with 50 pounds of coffee worth $90 a pound to get a mixture that she will sell for $70 a pound. how many pounds of the & 60 coffee should be used?

Find an equation of the line perpendicular to the graph of 28x-7y=9 that passes through the point at (4,1)

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?