mathtoo

Thank you! Correct!

82-x-29=18, -x=18-82+29=-35, x=35.

Oh, yeah! Domain! That's how you write it! I see! Thank you!

For (3). Just take the constant to the other side, you're left with x and y= constant.

Here, I'll show you!  

0=-36x + 14y + 8 

0 = 18y -9 -27x

Best thing to do first: 36x - 14y = 8 - 0, 36x - 14y = 8

And, for the second equation: 27x - 18y = 0+9, 27x - 18y = -9.

Now, divide the first equation by 2 and the second equation by 9, because the x will end up as a canceling factor.

So, 18x-7y=4, 3x-2y=-1, try to make both x's equal, subtract find x, then solve for y!

Correct! That's how you do it!

Thank you, hectictar! Nice solution!

I think the answer is (B), because: After 12 years, the resale price finally hit 0, so 400/12=33.333 and goes on forever. 

So, the value drops $100 every 3 years, to make it, so it can work.

Thanks! I understand better!

Yes! Correct!

The distance in the plane, that is: Formula: \(\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\) . We have the points, (2a, a-4) and (4,-1).

\(\sqrt{(4-2a)^2+(-1-a-4)^2}=2\sqrt{10}\), so we get a=1, a=1/5. So, there are two values! Thus, 1*1/5=1/5!