How do i solve 7x^{2} +11y^{2} =40

You decide instead to take the train there. the train will take 135 minutes. convert this into hours and minutes.

Hector and alex traded video games. alex gave hector one fourth of his video games in exchange for 6 video games. then he sold 3 video games and gave 2 video games to his brother. alex ended up with 16 video games. how many video games did alex have when he started?

Erik buys 2.5 pounds of cashews. if each pound of cashews costs $7.70, how much will he pay for the cashews?