2、
1505 - 75 × 3 = 1280
1280 ÷ (75+85)= 8 minutes
Xiaohua walks 3+8= 1 1 minute, and the school is 825 meters away from Xiaohua's home.
Equation: Xiaohua walks for x minutes and Xiaohong walks for y minutes.
x - y =3
75x + 85y = 1505
2 After adding 1 formula× 85 to the formula, omit y, 85x+75x=3*85+ 1505, x =1,75x=825.