Sin*-1 < can you explain this

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

Find the value of the combination. 5 c 5

Several paint mixtures are made by mixing blue paint and white paint. paint colors blue paint white paint mixture a 5 cups 12 cups mixture b 6 cups 6 cups mixture c 4 cups 12 cups mixture d 5 cups 6 cups which mixture has the highest ratio of blue paint to white paint