1. Use what you have learned to find the solutions of the polynomial equation shown below.

1 answer:

4 0

If (x^2 -10) is one of the factors, that can be further factored into:
(x - sqrt(10) ) * (x+sqrt(10)) =0
making 2 of the 4 solutions equal:
3.1623 and -3.1623

I then used an algebraic long division calculator
http://calculus-calculator.com/longdivision/
to calculate:
x^4 + 5x^3 ‒ x^2 ‒ 50x ‒ 90 divided by x^2 -10 which equals

x^2 + 5x + 9

Using the quadratic formula, the roots of that equation are:
x = -5 + sqrt (-11) / 2
and
x = -5 - sqrt (-11) / 2

Both of those roots are not real.

I tried using online graphing calculators for x^4+5x^3-x^2-50x-90=0 but none worked.

2. For this equation,
3x^2 ‒ 8x + k = 0
I used my OWN quadratic formula calculator
http://www.1728.org/quadratc.htm
and found that real roots no longer exist after "k" is greater than 5.3

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At 10 percent interest, how long does it take to quadruple your money?

horsena [70]

It takes about 14.55 years for quadruple your money

Solution:

Given that,

At 10 percent interest, how long does it take to quadruple your money

Rule of 144:

The Rule of 144 will tell you how long it will take an investment to quadruple

Here,

Rate of interest = 10 %

Therefore, number of years to quadruple your money is obtained by dividing 144 by 10

Rule of 144 Formula:

$N = \frac{144}{R}$

Where:

N = Number of many years times.

144 = Is the constant variable.

R = Rate of interest.

$\rightarrow N = \frac{144}{10} = 14.4$

Thus it takes about 14.4 years for quadruple your money.

Another method:

If initial amount is $ 1 and it if quadruples it should be $ 4

We have to find the number of years if rate of interest is 10 %

Let "n" be the number of years

Then we can say,

$Amount = Principal(1+\frac{R}{100})^n$

$4 = 1(1+\frac{10}{100})^n$

$4 = 1(1+0.1)^n\\\\4= 1(1.1)^n\\\\4 = 1.1^n\\\\We\ know\ that,\\\\(1.1)^{14.55} = 1.1^n\\\\We\ know\ that\\\\If\ a^m = a^n\ then\ m = n\\\\Therefore,\\\\14.55 = n\\\\n = 14.55$