Question

two speedboats leave the dock at the same time and travel in opposite directions. one travels 9 mi/hr faster than the other. After 2 hr the boats are 170 mi apart. How fast is each boat travelling ?

Answer 1

Answer:
`(170)/(X)`+
`(170)/(X-9)`=2

(=)17 0x +170x+1530=2x²+18x

(=)-2 x² +322x+1530=0

Δ=b²-4ac

Δ=115924

`\sqrt{}`Δ=340,476>0

because Δ>0 so that 2 X

=>x₁=2 (true), x₂=-161(false)

X+9= 2+9=11

first travel 2 mi/hr

second travel 11 mi/hr

Explanation: