Answer:
3, 5, 7, 9, 11, .........
Step-by-step explanation:
Given
= n(n + 2) , then
S₁ = 1(1 + 2) = 1(3) = 3 ⇒ a₁ = 3
S₂ = 2(2 + 2) = 2(4) = 8
S₃ = 3(3 + 2) = 3(5) = 15
Thus
a₂ = S₂ - S₁ = 8 - 3 = 5
a₃ = S₃ - S₂ = 15 - 8 = 7
The first 3 terms are 3, 5, 7
This is an AP with common difference d = 2, then
a₄ = a₃ + 2 = 7 + 2 = 9
a₅ = a₄ + 2 = 9 + 2 = 11
and so on
Answer:
Step-by-step explanation:
We assume the middle term is supposed to be 4x.
We can remove a common factor of 4 to simplify this a bit.
x^2 +x -5 = 0
This is of the form
ax^2 +bx +c = 0
where a=1, b=1, c=-5.
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The <em>quadratic formula</em> gives the solutions as ...
Filling in the given coefficients, we have ...
x = (-1 ±√(1^2 -4·1·(-5)))/(2·1)
x = (-1±√21)/2
The solutions are x = -1/2(1 +√21) and -1/2(1 -√21).
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<em>If what you wrote is what you intend</em>, then the equation simplifies to 4x^2 -16 = 0.
Dividing by 4 and factoring the difference of squares gives ...
x^2 -4 = 0
(x -2)(x +2) = 0
These factors are zero (hence their product is 0) for the values x = 2 and x = -2.
The solutions are x=2 and x=-2.