Solution: 3+2r=4-5r
2r+5r=4-3
7r= 1
r= 1/7
the second question
Meaning of the question: F. 1 class 25+2y, including 35-y girls and 7 boys who don't wear glasses. F. 1 How many boys wear glasses in class?
Solution: Boys have 25+2y-(35-y) = 25+2y-35+y = 3y-10.
Boys wear glasses 3y- 10-7=3y- 17.