I am unsure about the very last problem but I can help with the first two
1) (y+1)+4
If we combine the numbers 1 and 4, we get +5 and can isolate the numbers from the variable.
This would give us

2) (6*r)*7
remember that we do not have to explicitly state 6*r
Instead, we can write it as 6r
this helps us get rid of the parentheses
now we can write it as

I hope this helps!:)
Answer:
B. Pyramid
Step-by-step explanation:
<span> the angle that the Main Angle is called reference angle
</span><span>Given angle - 180
</span><span> 225° -180
</span>=45
eference angle for 225° is 45
Answer:
The standard deviation (σ) = 0.05
Step-by-step explanation:
The question is to find the standard deviation.
STEEP 1: FIND THE MEAN
(10+9.9) ÷ 2 = 9.95
STEP 2: SQUARE THE DIFFERENCE BETWEEN SPRINT TIME AND MEAN
10-9.95= 0.05
0.05^2 = 0.0025
9.9 - 9.95= -0.0025
-0.0025^2 = 0.0025
STEP 3: FIND THE VARIANCE
0.0025+0.0025= 0.005
0.005/2= 0.0025
STEP 4: FIND THE STANDARD DEVIATION (σ )
√variance
√0.0025 = 0.05
Therefore
σ = 0.05.
From the standard deviation, the percentage probability of the higher value to occurs is
0.05×100= 5%
That means Doug has 95%
And Bob has 5%