Which expression shows the sum of a number and its additive inverse?A.–10 – 10B.10 – (–10)C.10 + (–10)D.–10 + (–10)
2 answers:
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Answer:
A
Step-by-step explanation:
The diagonals of a parallelogram bisect each other. Hence, the two shorter sides created on diagonal RT ("6x-7" and "x+28" ) are equal.
<em>We can set them equal and solve for x:</em>
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<em>So the side length of 6x -7 is:</em>
<em>6(7)-7 = 35</em>
<em>and the side length of x + 28 is:</em>
<em>7 + 28 = 35</em>
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<em>THus, the diagonal RT = 35 + 35 = 70 units</em>
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<em>Answer choice A is right.</em>
Answer:
see explanation
Step-by-step explanation:
Given
9n² - n - = 0 ← multiply through by 3 to clear the fraction
27n² - 3n - 2 = 0 ← factoring
Consider the factors of the product of the n² term and the constant term which sum to give the coefficient of the n- term
product = 27 × - 2 = - 54 and sum = - 3
The factors are - 9 and + 6
Use these factors to split the n- term
27n² - 9n + 6n - 2 = 0 ( factor the first/second and third/fourth terms )
9n(3n - 1) + 2(3n - 1) = 0 ← factor out (3n - 1) from each term
(3n - 1)(9n + 2) = 0
Equate each factor to zero and solve for n
3n - 1 = 0 ⇒ 3n = 1 ⇒ n =
9n + 2 = 0 ⇒ 9n = - 2 ⇒ n = -