Using Letters to Represent Unknown Values

Let the unknown number be $x$. Write expressions for:

the fraction obtained when double the unknown number is divided by the sum of the unknown number and four.

Let the unknown number be $x$. Write expressions for:

a number which is twice $x$ more than $x$.

Let the unknown number be $x$. Write expressions for:

If the sum of the unknown number and its square is $x+x^k$ find $k$.

Let the unknown number be $x$. Write expressions for:

the sum of $-8$ and $x$.

Let the unknown number be $x$. Write expressions for:

ten times $x$.

Let the unknown number be $x$. Write expressions for:

six less than $x$.

Let the unknown number be $x$. Write expressions for:

three more than $x$.

Let the unknown number be $m$. Write expression for :

four times the unknown number less twice the number.

Let the unknown number be $m$. Write expression for :

a third of the unknown number plus three

Let the unknown number be $m$. 

If the cube of unknown number is $m^k$. Find $k$

Let the unknown number be $m$. Write expression for :

the difference between $25$ and the unknown number.

Let the unknown number be $m$. Write expression for :

a number that will exceed the unknown number by five

Let the unknown number be $m$. Write expression for :

the sum of the unknown number and $13$

Rewrite the expression in its simplest form: $\left(4\times x\right)÷\left(2\times x+4\times x\right)$

Rewrite the expression in its simplest form: $2\times \left(x+4\right)÷3$

Rewrite the expression in its simplest form: $3\times \left(x+1\right)÷2\times x$

Rewrite the expression in its simplest form: $2\times x\times \left(x-4\right)$

Rewrite the expression in its simplest form: $a\times 7-2\times b$

Rewrite the expression in its simplest form: $4\times x+5\times y$

Rewrite the expression in its simplest form: $m\times m\times m÷m\times m$