<em><u>Option B</u></em>
The result of addition is 2y = 24
<em><u>Solution:</u></em>
Given that we have to add the equations
<em><u>Given equations are:</u></em>
5x - y = -1
-5x + 3y = 25
We have to add both equations
This is similar to adding numbers. i,e 1 + 2 = 3
<em><u>For adding variables,</u></em>
When adding or subtracting terms that have exactly the same variables, you either add or subtract the coefficients, and let the result stand with the variable.
Example: 2x + 3x = 5x
Keeping this in mind, let us add the given equations
5x - y = -1
-5x + 3y = 25
----------------------------
0 + 2y = -1 + 25
[ 5x and -5x cancels each other. Combine -y and 3y which gives 2y]
2y = 24
Thus Option B is correct
Answer:
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Answer:
Step-by-step explanation:
Since the life span of the battery pack is known to be Normally distributed, we would apply the formula for normal distribution which is expressed as
z = (x - µ)/σ
Where
x = life spans of battery packs.
µ = mean life span
σ = standard deviation
From the information given,
µ = 250 hours
σ = 20 hours
The probability that a battery pack lasts longer than 260 hours. It is expressed as
P(x > 260) = 1 - P(x ≤ 260)
For x = 260
z = (260 - 250)/20 = 0.5
Looking at the normal distribution table, the probability corresponding to the z score is 0.69
The percentage of battery packs that lasts longer than 260 hours is
0.69 × 100 = 69%
The answer would be C. Obtuse Iscosceles