Answer:
see explanation
Step-by-step explanation:
Given
x² - 3x - 40 = 0
Consider the factors of the constant term (- 40) which sum to give the coefficient of the x- term (- 3)
The factors are - 8 and + 5, since
- 8 × 5 = - 40 and - 8 + 5 = - 3, thus
(x - 8)(x + 5) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 8 = 0 ⇒ x = 8
x + 5 = 0 ⇒ x = 5
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Given
4x² - 81 = 0 ← this is a difference of squares and factors in general as
a² - b² = (a + b)(a - b), thus
4x² - 81
=(2x)² - 9²
= (2x + 9)(2x - 9) = 0 ← in factored form
Equate each factor to zero and solve for x
2x + 9 = 0 ⇒ 2x = - 9 ⇒ x = - 
2x - 9 = 0 ⇒ 2x = 9 ⇒ x =
Sharon would spend $2.50 for the light bulbs she wants.
Answer:
4 2/7 - 6/7 = 24/
7
= 3 3/
7
Step-by-step explanation:
Conversion a mixed number 4 2/
7
to a improper fraction: 4 2/7 = 4 2/
7
= 4 · 7 + 2/
7
= 28 + 2/
7
= 30/
7
To find a new numerator:
a) Multiply the whole number 4 by the denominator 7. Whole number 4 equally 4 * 7/
7
= 28/
7
b) Add the answer from previous step 28 to the numerator 2. New numerator is 28 + 2 = 30
c) Write a previous answer (new numerator 30) over the denominator 7.
Four and two sevenths is thirty sevenths
Subtract: 30/
7
- 6/
7
= 30 - 6/
7
= 24/
7
For adding, subtracting, and comparing fractions, it is suitable to adjust both fractions to a common (equal, identical) denominator. The common denominator you can calculate as the least common multiple of both denominators - LCM(7, 7) = 7. In practice, it is enough to find the common denominator (not necessarily the lowest) by multiplying the denominators: 7 × 7 = 49. In the following intermediate step, it cannot further simplify the fraction result by canceling.
In other words - thirty sevenths minus six sevenths = twenty-four sevenths.
Answer: that's false
Step-by-step explanation:
degrees of freedom=(r-1)(c-1)
If I'm wrong I'm sorry
Answer:
Step-by-step explanation:
we have
we know that
substitute
