Solve for k 7(9+k)=84

Asmall foreign car gete 42 miles per gallon and user 35 gallons on a trip.gasoline costs $1.05 per gallon.what was the cost of gasoline per mile driver?

At oaknoll school, 90 out of 270 students on computers. what percent of students at oak knoll school do not own computers? round the nearest tenth of a percent.

Given that sin∅ = 1/4, 0 < ∅ < π/2, what is the exact value of cos∅? a. (√4)/4 b. (√15)/4 c. (4π)/2 d. (4√2)/4