If it has rational coefients and is a polygon
if a+bi is a root then a-bi is also a root
the roots are -4 and 2+i
so then 2-i must also be a root
if the rots of a poly are r1 and r2 then the factors are
f(x)=(x-r1)(x-r2)
roots are -4 and 2+i and 2-i
f(x)=(x-(-4))(x-(2+i))(x-(2-i))
f(x)=(x+4)(x-2-i)(x-2+i)
expand
f(x)=x³-11x+20
Answer:
[A] (4 ÷ 2)+(0.8 ÷ 2)
Step-by-step explanation:
Divide the 2 into each digit, which must be in the same spot it was before:
Knowing that 8 in 4.8 ⇒ 0.8
Thus, you can infer that [B] is wrong
You also infer that [D] and [C] is wrong because 4 is a whole number.
Thus, that left us with [A] 4 ÷ 2+0.8 ÷ 2 which shows the quotient of 4.8 ÷ 2
Hence, [A] 4 ÷ 2+0.8 ÷ 2 is the answer.
<em>~Learn with Lenvy~</em>
Answer:
W ≈ 5.2 cm
Step-by-step explanation:
Represent the length and width by L and W respectively.
Then L * W = 81 cm^2, and L = 3W.
Substituting 3W for L in the first equation, we get:
3W * W - 81 = 0, or 3W^2 - 81 = 0.
To make it easier to find the final answer, rewrite 3W^2 - 81 = 0 as
81
W^2 = ------- = 27
3
Then W (the width) is the positive square root of 27, or W ≈ 5.2 cm
Answer:
ok
Step-by-step explanation:
For quadratics, these formulas are used mainly for factoring.
Your equation can be written as ...
... 2(x² +2x -3) = 0
You factor this by looking for factors of -3 (c=x1·x2) that add to give +2 (b=-(x1+x2)). These are {-1, +3}, so the factorization is ...
... 2(x -1)(x +3) = 0
The roots are then 1 and -3, which sum to -b = -2.
(You will note that the numbers used in the binomial factors are the opposites of the roots x1 and x2 in the Viete's Formulas. That is how we can look for them to sum to "b", rather than "-b".)
