PLS HELP THANK UUU!!!

47.45754235

31.46697634

Hey do you need to show your work for these? I found an answer key

Step-by-step explanation:

We need to use law of cosines

c²=a²+b²-2abcos(C)

let x= angle xzy

plugging in what we have the equation looks like

17²=22²+20²-2*22*20*cos(x)

289=484+400-880cos(x)

.676136364=cos(x)

x=47.45754235

b.)

The smallest angle should be opposite to the smallest side

Using the law of cosines again we get

9²=13²+17²-2*13*17*cos(x)

81=458-442cos(x)

.852941176=cos(x)

x=31.46697634

- "runner b is moving at a slower rate."

- "the graphs shown are graphs of distance(km) against time(min).

the slopes of this graphs are are given by:

slope = (change in y)/(change in x)

= (change in distance)/(change in time)

this is the formula for finding the speed. so, the slope of these graphs represent the speed of the runner.

taking each division in the graph to represent 1 on both axis:

runner a ⇒ speed = (2-0)/(1-0)

= 2/1

= 2 km/min

runner b ⇒ speed = (3-0)/(3-0)

= 3/3

= 1 km/min

this shows that   runner b is moving at a slower rate."

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!