solve 2zx^2y = 18 where x = 1 and z = y

[almandy]

2zx^2y = 18 where x = 1 and z = y

I have solved for exponent square which is one squared which is one then which gave me 2z1=18 which is 2z =18 i divide each side by 2 and got nine but when plugged in it is not correct answer would just like to know how to solve this problem thank you

 

[jonboy]

Hi almandy!

You can't solve just for a variable w/half of the problem at once. The equation is balanced right now and taking parts out make it unbalanced (the \(\displaystyle y\)), unless you do the same thing to both sides of the equation.

\(\displaystyle \L \;2zx^{2}y\,=\,18\)

Substitute \(\displaystyle z\) for \(\displaystyle y\):\(\displaystyle \L \;2z^2z\,=\,18\)

\(\displaystyle \L \;2z^{3}\,=\,18\)

I've gotta go, can you finish? If not show us what you think and ask some q's :idea:

 

[stapel]

2zx^2y = 18 where x = 1 and z = y

Your formatting is ambiguous. Do you mean either of the following?

. . . . .2 z x^2y = 18

. . . . .2 z x² y = 18

Or do you mean something else?

Note: If z = y, then you can replace one of those variables with the other. Once you plug "1" in for "x", you'll then be left with an equation in one variable.

I have solved for exponent square which is one squared which is one then which gave me 2z1=18 which is 2z =18 i divide each side by 2 and got nine but when plugged in it is not correct answer

I'm sorry, but I can't make heads or tails of this. Please reply with a corrected version (using standard punctuation, capitalization, spelling, grammar, and terminology), so we can tell when you mean. (If English is not your first language, please get help from somebody who is more familiar with the language.)

Thank you.

Eliz.

 

[skeeter]

2zx^2y = 18 where x = 1 and z = y

\(\displaystyle \L 2zx^2y = 18\)

substitute 1 for x and y for z ...

\(\displaystyle \L 2y(1^2)y = 18\)

\(\displaystyle \L 2y^2 = 18\)

\(\displaystyle \L 2y^2 - 18 = 0\)

\(\displaystyle \L 2(y^2 - 9) = 0\)

\(\displaystyle \L 2(y+3)(y-3) = 0\)

\(\displaystyle \L y = z = \pm 3\)