Trình bày khái niệm và cách giải phương trình bậc nhất 1 ẩn, hệ phương trình bậc nhất 2 ẩn

Mr. vasquez determines that the area of a bathroom is in his house is 25 square feet less than one-fifth of the area of the living room if the bathroom measures 35 square feet what is the area of the living room

Cora bought a package of erasers. there are 4 pink erasers and 12 blue erasers. what is the ratio of pink erasers to blue erasers?

How do i start to solve? would appreciate a walk-thru! a bird sitting 16ft above the ground in an apple tree dislodges an apple. after how many seconds does the apple land on the ground? (assuming that no branches will interfere with it's fall)