Formula help with this equation

Question

I don't know what the answer to this formula is, can someone please help me.

I've tried lots of things but getting no where.

If $x=\dfrac56+\dfrac{15}{18}-\dfrac{10}{12}$, then $(x-1)3=$ ?

Answer 1

The expression $x=5/6+15/18-10/12$ may be simplified considerably:

\begin{align*} x &= \frac{5}{6}+\frac{15}{18}-\frac{10}{12}\\ &= \frac{5}{6}+\left(\frac{30}{36}-\frac{30}{36}\right)\\ &= \frac{5}{6}. \end{align*}

Thus, $x-1=-\frac{1}{6}$ and $3(x-1)=-\frac{1}{2}$.

As @ParthKohli has pointed out in a comment, you may actually be interested in the expression $(x-1)^3$, rather than in $(x-1)3$. If that's the case, you can still use the simplification for $x$ provided above to obtain $$(x-1)^3=-\frac{1^3}{6^3}=-\frac{1}{216}.$$

Answer 2

\begin{align} x&=5/6+15/18-10/12\\ x-1&=5/6+15/18-10/12- 3/3\\ (x-1)3&=(5/6+15/18-10/12- 3/3)3\\ (x-1)3&=3*5/6+3*15/18-3*10/12- 3*3/3\\ (x-1)3&=5/2+15/6-10/4- 3\\ (x-1)3&=5/2+5/2-5/2- 3\\ (x-1)3&=5/2- 3\\ (x-1)3&=5/2- 6/2\\ (x-1)3&=-1/2 \end{align}