Can someone me find the y-intercept and explain how you got that answer?

3x + 4y = 5 x- 3y = -7 solve by substitution

The dance committee of pine bluff middle school earns $72 from a bake sale and will earn $4 for each ticket they sell to the spring fling dance. the dance will cost $400 write an inequality to determine the number, t of tickets the committee could sell to have money left over after they pay for this year's dance. what is the solution set of the inequality?

Emily convinced her mom to buy a giant box of her favorite cereal. her mom doesn't think the box will fit on their shelf. the volume of the box is 1000 cm^3 . the base of the box is 25 cm by 10 cm