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Re: how much percentage (off) of $45.90 is $30.00?

I don't know what the 'off' is there for.  I am assuming it is a typo.

The fraction is   30/45.90

So the percentage is 30/45.9 * 100%

You can finish it.

(-5-7i)-(-8+4i)

=-5-7i+8-4i

=-5+8-7i-4i

=3-11i

"of" usually means "multiply"

So, convert the "50%" to a decimal = .50    

And we have

.50 X 100

And I'll let you finish this.....

Thanks, Anonymous...I made a slight error in transcribing the problem.....sorry!!

Let me correct this

(x+4) (x-4)  - (x-4) (3x+5)

Since (x-4) is common to both terms, we can factor it out, and this gives us

(x-4) [(x+4) - (3x + 5)]  Now, simplifying the stuff in the brackets, we have

(x-4) (-1 - 2x) =

(x - 4) (1 + 2x) (-1) =

(-1) (x - 4) (1 + 2x)    And multiplying (-1) across (x-4) we end up with

(4 - x) (1 + 2x)

And that's it !!!

Jarvis had $10. He now has $15. What was the percent change

We're trying to find  the % increase

This is given by

(New - Old) / (Old)

So we have

(15 - 10) / 10   =

5 / 10   = 

50 / 100   =

50% increase

how do i write 14400000 inscientific notation

1.44 x 10^7

As a decimal 8/108 = 0.074 repeating, as in the first post.

you can by dividing by 2 from the number the u are finding the square root  

0.233 answer

0.074 repeating

5^-4 =

1 / (5^4) =

1 / (5*5*5*5) =

1 / 625

There you go !!

answer to 3y2-2y-8

I assume you want to facor this...it's just

(3y + 4) (y - 2 )

That's it !!!

Usually you would use a calculator for sqrt's but you kinda of memorize the 1st 15 sqrt's after a while.

The answer is 12 btw.

The integer 2 is the same as the number 2 so...

it is 2+2=

4

No, usually you have to push "2nd" button which is located usually located at the top left side of the calculator.

OK...this one isn't too difficult.....note that the first thing is just a difference of two squares, so we can write it as (x+4) (x-4)   

And we have

(x+4) (x-4)  - (x-4) (3x-5)

Since (x-4) is common to both terms, we can factor it out, and this gives us

(x-4) [(x+4) - (3x -5)]  Now, simplifying the stuff in the brackets, we have

(x-4) (9 - 2x)

Above solution is incorrect

Correct is solution

Depends on what kind of pie we have.......

what is 4^6*x^8y^-2/ 4^7*x^4y^2

So we have

[(4^6)*(x^8)*(y^-2)] / [(4^7) * (x^4) 8 (y^2)]

So, by the property of exponents that says that  (a^n) /  (a^m)   =  a^(n-m)  We can write

[4^(6-7)] * [x^ (8-4)] * [y^(-2-2)]  =

[4^(-1)] * [x^4] * [y^(-4)] =

[x^4] / [4 * y^(4)]

simplify (64)x^9)^(1/3)

OK...here's what we really have

64^(1/3) * (x^9)^(1/3) =

4 * (x) ^( 9 * (1/3)) =

4 * x^(3) =

4x^3

And that's all......

Thank you

Re: Factorise fully: (x^2-16) - (x-4)(3x+5)

OK...this one isn't too difficult.....note that the first thing is just a difference of two squares, so we can write it as (x+4) (x-4)   

And we have

(x+4) (x-4)  - (x-4) (3x-5)

Since (x-4) is common to both terms, we can factor it out, and this gives us

(x-4) [(x+4) - (3x -5)]  Now, simplifying the stuff in the brackets, we have

(x-4) (9 - 2x)

And that's it !!!

You can estimate the square root of a number n by iterating the expression (1/2)(n+2/n).  That is, you get the first estimate by n1 = (1/2)(n+2/n), then the second, better, estimate by n2 = (1/2)(n1+2/n1), then the third estimate by n3 = (1/2)(n2+2/n2) and so on.  However, you will probably still need a calculator to do these calculations!!

-2log8(x + 1) = -8

It's a little difficult to tell what you're using as the base ....if it's 10, we have this

Let's divide both sides by -2   This gives

log8(x + 1) = 4

Writing in exponential form, we have

10^4 = 8 (x + 1)   Therefore

10,000 = 8(x + 1)   Now, divide both sides by 8  This gives

1250 = x +1      Subtracting 1 from both sides gives us

x = 1249

However, if you're using 8 as the base, let's take it from this point

log8(x + 1) = 4

Now, let's write this in exponential form using base 8......we have

8^4 = x +1

4096 = x + 1    And subtracting 1 from each side gives us

x = 4095

I suspect that the second thing might be what you meant, but anyway, you have answers using both bases!!!   

The volume of a cylinder is given by pi*r^2*h where r is the radius and h is the height.  So pi*2^2*h = 100

therefore h = 100/(pi*4) cm or

 $${\mathtt{h}} = {\frac{{\mathtt{100}}}{\left({\mathtt{\pi}}{\mathtt{\,\times\,}}{\mathtt{4}}\right)}} = {\mathtt{h}} = {\mathtt{7.957\: \!747\: \!154\: \!594\: \!766\: \!8}}$$