7y 12=-4(y-4) a.-1 5/11 b.4/11 c.-11/16 d. 2 3/4

To travel 105 miles, it takes Sue, riding a moped, 3 hours less time than it takes Doreen to travel 64 miles riding a bicycle. S

Volgvan

Let t=time Doreen travels; let r=rate of Doreen

RATE * TIME = DIST.
Sue | r+13 t-3 105
Doreen | r t 64

Now solve the system:
(r+13)(t-3)=105
r*t=64

 $r= \frac{64}{t} 
\\
\\(\frac{64}{t} +13)(t-3)=105 
\\
\\64- \frac{192} {t}+13t-39-105=0
\\
\\13t- \frac{192} {t}-80=0
\\
\\ 13t^2-80t-192=0
\\
\\t_{1,2}= \frac{80\pm \sqrt{(-80)^2-4\times13(-192)} }{2\times13}= \frac{80\pm128}{26} 
\\
\\t=\frac{80+128}{26} =8
\\
\\r=\frac{64}{t} =\frac{64}{8} =8$ 

Doreen: rate = 8 mph, time = 8 hours
Sue: rate = 21 mph, time = 5 hours

8 0

3 years ago

PLSSSSSSSSSSSSSSSSSSSSSSSS HELP ME!!

zzz [600]

Answer:

For the top table:

[x] | 3.1 | 2.5 | 1.2 | 0.9 | 0.14 | 0.06 | 0.02 |

[y] | 15.5 | 12.5 | 6 | 4.5 | 0.7 | 0.3 | 0.1 |

For the bottom table:

k = 5

[x] | 3.1 | 2.5 | 1.2 | 0.9 | 0.14 | 0.06 | 0.02 |

[y] | 15.5 | 12.5 | 6 | 4.5 | 0.7 | 0.3 | 0.1 |

3 0

2 years ago

Please help I'll give brainliest to the correct person

elena55 [62]

Answer:

the first one because supplementary means angles which add up to 180 and 180 degrees is a straight line and the third one because they both share the same vertex and side

Step-by-step explanation:

8 0

2 years ago

Subtract: (b^2 + 9 ab + 5a ) - ( 3b^2 -25ab + 1)

Brrunno [24]

Answer:

- 2b^2 + 34ab + 5a - 1

Step-by-step explanation:

here's your solution

=> (b^2 + 9ab + 5a) - (3b^2 - 25ab + 1)

=> b^2 + 9ab + 5a - 3b^2 + 25ab - 1

=> - 2b^2 + 34ab + 5a - 1

hope it helps

6 0

2 years ago

Amber has 2 red crayons,5 blue crayons,and 4 yellow crayons.how many crayons does she have

Gelneren [198K]

All you have to do is addition. 2+5+4=11. Or you can break it down and go 2+5=7 and then 7+4=11. Or 5+4=9 then 9+2=11. Or 4+2=6 then 6+5=11.

6 0

2 years ago

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