Square of (a + 3) - (A-1)

Square of (a + 3) - (A-1)

Original formula = a ^ 2 + 6A + 9 - (a ^ 2-2a + 1)
=6a+2a+9-1
=8a+8

Xiaoming and Xiaofang start from home to school respectively. Xiaoming takes 15 more miles than Xiaofang, and Xiaofang takes 18 more time than Xiaoming. So the speed ratio of Xiaoming and Xiaofang is ()
A. 5：8B. 8：5C. 27：20D. 16：15

Xiaoming's speed: (1 + 15) △ 1 = 65, Xiaofang's speed: 1 △ 1 + 18 = 89, the ratio of Xiaoming's speed to Xiaofang's speed is: 65:89 = 27:20, so choose: C

Xiaoming and Xiaofang start from home to school respectively. Xiaoming takes 15 more miles than Xiaofang, and Xiaofang takes 18 more time than Xiaoming. So the speed ratio of Xiaoming and Xiaofang is ()
A. 5：8B. 8：5C. 27：20D. 16：15

Xiaoming's speed: (1 + 15) △ 1 = 65, Xiaofang's speed: 1 △ 1 + 18 = 89, the ratio of Xiaoming's speed to Xiaofang's speed is: 65:89 = 27:20, so choose: C