1. ## Please help it's been too long since I took algebra, I've been stuck on this problem

Six times the quantity of 4 minus a number is 15. Find the number. Show your work. This should be easy to pros. Thanks

2. ## Re: Please help it's been too long since I took algebra, I've been stuck on this prob

Model the problem like this:
x is the quantity needed
x - 4 the quantity minus 4
six time the quantity minus 4 is: ______________fill the blank
the last one is = 15.
Find the quantity.

Does this help

3. ## Re: Please help it's been too long since I took algebra, I've been stuck on this prob

Use symbols for the words.

$\begin{matrix}\mbox{Six} & \mbox{times} & \mbox{the quantity of} & 4 & \mbox{minus} & \mbox{a number} & \mbox{is} & 15 \\ 6 & \times & ( & 4 & - & x & )= & 15\end{matrix}$

So, solve for $x$

4. ## Re: Please help it's been too long since I took algebra, I've been stuck on this prob

Ok thanks but I need to see the whole problem to understand it...I'm not getting the same answer that's in the back of the book which is 1.
I multiplied 6 times 4 and got 24 then 6 times x which is 6x...I added 24 to both sides and got 15 + 24 which is 39 on the right and divided that by 6 and MY answer was 6 and 1/2 but the answer is 1.5. What did I do wrong...HELP! thanks

5. ## Re: Please help it's been too long since I took algebra, I've been stuck on this prob

\begin{align*}6(4-x) & = & 15 \\ 24 - 6x & = & 15 \\ -24 & & -24 \\ \hline -6x & = & 15-24 \\ -6x & = & -9 \\ \times -\tfrac{1}{6} & & \times -\tfrac{1}{6} \\ \hline x & = & \dfrac{9}{6} \\ x & = & \dfrac{3}{2}\end{align*}

6. ## Re: Please help it's been too long since I took algebra, I've been stuck on this prob

See I multiplied 24 by both sides I get confused as to how do I know I'm not supposed to do that.

7. ## Re: Please help it's been too long since I took algebra, I've been stuck on this prob

You had 24-6x = 15. If you add 24 to both sides, you get (24 - 6x) + 24 = 15 + 24. Add this up, and now you have 48 - 6x = 39. You are trying to get all terms with an x on one side and all numbers on the other. So, adding 24 to both sides did not help at all. So, you try subtracting 24 from both sides. 24 - 6x - 24 = 15 - 24. Since 24-24 = 0, on the left hand side, you are only left with -6x. On the right hand side, 15-24 = -9.

Thank you...

9. ## Re: Please help it's been too long since I took algebra, I've been stuck on this prob

Originally Posted by Tlcmel
See I multiplied 24 by both sides I get confused as to how do I know I'm not supposed to do that.