Answer:
Gabriella's average original speed was 56 ![\frac{mi}{h}](https://tex.z-dn.net/?f=%5Cfrac%7Bmi%7D%7Bh%7D)
Step-by-step explanation:
Let's use the equation that defines the average speed "v" of Gabriella during the time (t) that her trip took:
![v = \frac{distance}{time} \\v=\frac{400}{t}](https://tex.z-dn.net/?f=v%20%3D%20%5Cfrac%7Bdistance%7D%7Btime%7D%20%5C%5Cv%3D%5Cfrac%7B400%7D%7Bt%7D)
Next let's write a similar average speed equation for the case in which she drove at (v - 7 mi/h) during the same time "t" and covered 350 miles:
![(v-7)=\frac{350}{t}](https://tex.z-dn.net/?f=%28v-7%29%3D%5Cfrac%7B350%7D%7Bt%7D)
Notice that the time "t" in the denominator appears equally in both equations we wrote, so let's isolate them on the right:
![\frac{v}{400} =\frac{1}{t} \\and\\\frac{(v-7)}{350} =\frac{1}{t}](https://tex.z-dn.net/?f=%5Cfrac%7Bv%7D%7B400%7D%20%3D%5Cfrac%7B1%7D%7Bt%7D%20%5C%5Cand%5C%5C%5Cfrac%7B%28v-7%29%7D%7B350%7D%20%3D%5Cfrac%7B1%7D%7Bt%7D)
now equal both expression since they both share the same value on the right, and solve for the unknown "v":
![\frac{v}{400} =\frac{(v-7)}{350} \\350\,v=400\,(v-7)=\\350\,v=400\,v-2800\\2800=50\,v\\v=\frac{2800}{50} \,\,\frac{mi}{h}\\v=56\,\,\frac{mi}{h}](https://tex.z-dn.net/?f=%5Cfrac%7Bv%7D%7B400%7D%20%3D%5Cfrac%7B%28v-7%29%7D%7B350%7D%20%5C%5C350%5C%2Cv%3D400%5C%2C%28v-7%29%3D%5C%5C350%5C%2Cv%3D400%5C%2Cv-2800%5C%5C2800%3D50%5C%2Cv%5C%5Cv%3D%5Cfrac%7B2800%7D%7B50%7D%20%5C%2C%5C%2C%5Cfrac%7Bmi%7D%7Bh%7D%5C%5Cv%3D56%5C%2C%5C%2C%5Cfrac%7Bmi%7D%7Bh%7D)
Answer:
False
Step-by-step explanation:
6 + (-7)n = 34
Plug in -7 for n and see if it's true:
6 + (-7)(-7) = 34
6 + 49 = 34
55 = 34
No, it's not true, so the mystery number is not -7.
Answer:
The x is for you to multiply <30
Answer:
22,260
Step-by-step explanation: