Evaluate 2x-y for x=3 and y= -2 A. 10 B. 14 C. 18 D. 20
1 answer:
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Answer:
a₁₃ = - 27x - 41
Step-by-step explanation:
The nth term of an arithmetic sequence is
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = - 3x + 7
d = a₂ - a₁ = - 5x + 3 - (- 3x + 7)
= - 5x + 3 + 3x - 7
= - 2x - 4
Then
a₁₃ = - 3x + 7 + 12(- 2x - 4)
= - 3x + 7 - 24x - 48
= - 27x - 41
Answer:
x ≈ 1.32, x ≈ - 5.32
Step-by-step explanation:
Given
x² + 4x - 7 = 0 ( add 7 to both sides )
x² + 4x = 7
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(2)x + 4 = 7 + 4
(x + 2)² = 11 ( take the square root of both sides )
x + 2 = ± ( subtract 2 from both sides )
x = - 2 ±
Thus
x = - 2 - ≈ - 5.32 ( to 2 dec. places )
x = - 2 + ≈ 1.32 ( to 2 dec. places )