Ur equations are :
C = 0.03t + 20...this is company A
C = 0.07t + 5....this is company B

now...for them to be equal...set them equal and solve for t
0.03t + 20 = .07t + 5
-5 + 20 = 0.07t - 0.03t
15 = 0.04t
15/0.04 = t
375 = t.......there would have to be 375 texts

4 0

2 years ago

Find all the zeros of the equation x^4-6x^2-7x-6=0

rusak2 [61]

Answer:

The zeros are

$x=-2,\:x=3,\:x=-\frac{1}{2}+i\frac{\sqrt{3}}{2},\:x=-\frac{1}{2}-i\frac{\sqrt{3}}{2}$

Step-by-step explanation:

We have been given the equation x^4-6x^2-7x-6=0

Use rational root theorem, we have

$a_0=6,\:\quad a_n=1$

$\mathrm{The\:dividers\:of\:}a_0:\quad 1,\:2,\:3,\:6,\:\quad \mathrm{The\:dividers\:of\:}a_n:\quad 1$

$\mathrm{Therefore,\:check\:the\:following\:rational\:numbers:\quad }\pm \frac{1,\:2,\:3,\:6}{1}$

$-\frac{2}{1}\mathrm{\:is\:a\:root\:of\:the\:expression,\:so\:factor\:out\:}x+2$

$=\left(x+2\right)\frac{x^4-6x^2-7x-6}{x+2}\\$

$=x^3-2x^2-2x-3$

Again factor using the rational root test, we get

$=\left(x+2\right)\left(x-3\right)\left(x^2+x+1\right)$

Using the zero product rule, we have

$x+2=0:\quad x=-2\\x-3=0:\quad x=3\\x^2+x+1=0\\\\x_{1,\:2}=\frac{-1\pm \sqrt{1^2-4\cdot \:1\cdot \:1}}{2\cdot \:1}\\\\=-\frac{1}{2}+i\frac{\sqrt{3}}{2},\:x=-\frac{1}{2}-i\frac{\sqrt{3}}{2}$

Therefore, the zeros are

$x=-2,\:x=3,\:x=-\frac{1}{2}+i\frac{\sqrt{3}}{2},\:x=-\frac{1}{2}-i\frac{\sqrt{3}}{2}$

4 0

2 years ago

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Student made five tetrahedrons, a three dimensional figure with four triangular faces and labeled the faces 1-4. use an equation

JulsSmile [24]

The probability is 1/1024.

Each tetrahedron has a 1/4 chance of landing on 3, since there are 4 sides and only one of them is marked 3.

Each tetrahedron roll is independent, since no roll is affected by another.

This means we multiply the probabilities:
1/4(1/4)(1/4)(1/4)(1/4) = 1/1024

3 0

2 years ago

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Convert 67.5 cu ft to cubic yards.

Diano4ka-milaya [45]

I got 2.500 repeating :)

6 0

3 years ago

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