Answer:
Angle QPM and Angle LMP are alternate interior I'm pretty sure, so I think B or second choice.
∠DBC = 19° since the two angles have to add up to 180, if x = 23, then 23 -4 = 19 for the right, and 7 x 23 = 161, and 161 + 19 = 180.
The first step would be to plot the y-intercept, which in this case would be 1.
Lets call those two unknown numbers a, b and write the info in the problem as equations:
a*b = 30
a + b = 40
lets solve for a in the second equation and substitute in the first:
<span>a + b = 40
</span>a = 40 - b
therefore:
<span>a*b = 30
</span>(40 - b)b = 30
40b - b^2 = 30
b^2 - 40b + 30 = 0
if we apply the general quadratic equation to solve we have:
b = (40 +- √(1600 - 120))/2
b = (40 +- √(1480<span>))/2
</span>b = (40 +- 38.47)/2
There are two solutions:
<span>b1 = (40 + 38.47)/2
</span><span>b1 = 39.24
b2 = (40 - 38.47)/2
</span>b2 = 0.765
lets use the second solution <span>b2 = 0.765, and substitute in the first equation to find a:
</span><span>a*b = 30
</span>a*0.765 = 30
a = 30/0.765
a = 39.216
so the numbers are 39.216 and 0.765
The average time of the 20 athletes who did not qualify for the final is 11.2 seconds .
<u>Step-by-step explanation:</u>
Here we have , Twenty-eight athletes participate in a 100-meter race. The time of each athlete is measured during the qualification round. The average time is 11 seconds. The 8 athletes with the fastest time qualified for the final. The average time of these 8 athletes is 10.5 seconds. Let's have equations for this:
where 
are athletes
⇒ 
⇒ 
⇒ 
⇒ 
, where m is average time of the 20 athletes who did not qualify for the final.
⇒ 
⇒ 
⇒ 
∴ The average time of the 20 athletes who did not qualify for the final is 11.2 seconds .
