What equation results from completing the square and then factoring? x2 + 10X = 15
1 answer:
Answer:
C) (x + 5)² = 40
Step-by-step explanation:
Given the quadratic equation, x² + 10x = 15:
To complete the square, take the coefficient of the middle term (b), and divide it by 2<em>a</em>:
x² + 10x + = 15 +
x² + 10x + = 15 +
x² + 10x + 5² = 15 + 5²
x² + 10x + 25 = 40
The trinomial on the left-hand side of the equation provides a perfect square binomial factors: <em>u</em>² + 2<em>uv</em> + v² = (<em>u</em> + <em>v</em>)²
x² + 10x + 25 = 40
(x + 5)² = 40
Therefore, the correct answer is Option C) (x + 5)² = 40
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Answer:
1,082
Step-by-step explanation:
The sample size n in Simple Random Sampling is given by
where
z = 1.645 is the critical value for a 90% confidence level (*)
s = 2 is the estimated population standard deviation
e = 0.1 mm points is the margin of error
so
rounded up to the nearest integer.
So the manufacturer should test 1,083 parts.
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(*)This is a point z such that the area under the Normal curve N(0,1) outside the interval [-z, z] equals 10% = 0.1
It can be obtained in Excel with
NORMINV(1-0.05,0,1)
and in OpenOffice Calc with
NORMINV(1-0.05;0;1)