I'll solve 21, and you then should be able to solve the rest on your own!
Since ADC is 135, that means that that whole angle is 135 degrees. In addition, since angles ADB and BDC add up to ADC, we get ADB+BDC=ADC=135=11x+9+7x=18x+9. Subtracting 9 from both sides, we get 126=18x. Dividing both sides by 18, we get x=7. Plugging that into 11x+9=BDC, we get 11*7+9=77+9=86
Answer:
About 3 years Speedy Jet printers be guaranteed.
Step-by-step explanation:
Given : Quality control studies for Speedy Jet Computer Printers show the lifetime of the printer follows a normal distribution with
mean 
and standard deviation 
If the company wishes to replace no more than 10% of the printers.
To find : How long should Speedy Jet printers be guaranteed ?
Solution :
Using Z- table,
Z value corresponding to 10% or 0.10 = -1.28.
Applying z-score formula,
The value of x is given by,
Substitute the values,
So, approx 3 years.
Therefore, About 3 years Speedy Jet printers be guaranteed.
5x+3y=58
5x-3y=22
(3y gets cancelled bc 3y-3y=0, then add 5x with 5x, so you're left with)
10x=80, (divide both sides by 10)
x=8
Now we look for y. So choose one formula from the two (let's say 5x + 3y=58)
Substitute x for 8 so it will look like---- 5(8)+3y=58
Multiply 5*8--- so you get -- 40+3y=58
Subtract 40 from both sides and you're left with 3y=18
divide both sides by 3
you get y=6
In conclusion, x=8 and y=6 hence, (8,6)
Answer:
Step-by-step explanation:
