mid terms in the morning - can anyone help?

[mogalvin]

23 years since I took algebra, so bear with me.

solve for z: x + zy = k - 3z.

I get to x + zy - k = -3z

x + zy - k = z
3

and then I get stuck

 

[Unco]

Perhaps you may remember this...

x + zy = k - 3z

Group z terms together.

zy + 3z = k - x

Factor out z:

z(y + 3) = k - x

Divide by (y+3):

z = (k - x)/(y + 3)

 

[mogalvin]

Thank you so much

Now it makes complete sense. You know the saying about old dogs and tricks

 

[Denis]

23 years since I took algebra, so bear with me.
solve for z: x + zy = k - 3z.
I get to x + zy - k = -3z
x + zy - k = z
3
and then I get stuck

Just in case: the denominator should be -3, not 3.

 

[Guest]

Last one of the day I promise.

1 over 2 sqrt 3+1 = 2 sqrt 3-1 over 11 true or false?

I have gotten MUCH better at this stuff honestly I am only posting a few of the problems that I have been doing. We have over 50 pages a week in the text, plus 30 or so homework problems, he gives us brain teasers, discussion questions and tests. So, I am getting there slowly.

We have nothing in the book showing me how to proceed with this. Could you steer me in the right direction?

 

[Guest]

Sorry I posted in your post. It has been a long day.

 

[Denis]

Re: Last one of the day I promise.

1 over 2 sqrt 3+1 = 2 sqrt 3-1 over 11 true or false?

Hmmm bethany...PLEASE use brackets; you'll go to your room with no
dessert if you keep this up :evil:

That should be shown like this:
1 / (2sqrt(3) + 1) = (2sqrt(3) - 1) / 11

We can cross-multiply next (like if a/b = c/d, then ad = bc):

(2sqrt(3) + 1)(2sqrt(3) - 1) = 11 * 1

(2sqrt(3))^2 - 1 = 11 : just like (x + y)(x - y) = x^2 - y^2

4*3 - 1 = 11 : 2^2=4 and sqrt(3)^2 = 3
12 - 1 = 11
Can you finish :wink: