Multiplying a Monomial by a Monomial

If Kavita bought $(3x+7)$ copies from the bookseller. If the cost of each copy is rupees $(2x–1)$, then if $x=5$, then  $x$ rupees did Kavita give to the bookseller, find the value of $x$.

The speed of a train is $(2x^2+x+4)$ km per hour.

If $x=5$ , then find the distance travelled by the train in the appropriate time in $km$.

There are $2x$ classes in a school. The number of students in each class is $(x^3+2x+2)$.

Find, If $x=3$ , then how many students are there in the school?

There are $2x$ beds in a field. Each bed has $xy$ rows. Each row has $y^2$ tomato plants. Find:

If $x=3$, $y=2$, then what is the total number of plants?

Find the value of following product: $2x\times (–10x{y}^2)\times 3x^{2}y, \mathrm{if} x=1,y=2$

Find the value of the product of the following: $x^2\times 7x^5\times \frac{1}{7}{x}^3 \times (–6 x), \mathrm{for} x=1$

Simplify: $a^2\left(b^2-c^2\right)+b^2\left(c^2-a^2\right)+c^2\left(a^2-b^2\right)$

Find the area of the given rectangle.

If $\left(5a+b\right)\left(2a+3b+5c\right)=10a^2+kab+mac+5bc+3b^2$, find the value of $k+m$.

Multiply $\left(2a^2-4ab+2b^2\right)$ by $\left(2a-b\right)$.Verify the result if $a=3$ and $b=2$.

If the product of $\left(2x+\frac{1}{3}\right)\left(3x-4\right)=6x^2-7x+k$. 

Then find the value of $k$.

If the product of $\left(\frac{3x}{4}+\frac{y}{7}\right)\left(\frac{3x}{4}-\frac{y}{7}\right)=\frac{9x^2}{k}-\frac{y^2}{49}$.

Then find the value of $k$.

If $x^2\left(2y^2\right)(-3z^2)=k{x}^m{y}^m{z}^m$ then $k+m=$_____.

Find the product: $8x\times (-2)$

Multiply the following expressions and represent them geometrically. $5\times 4\mathrm{y}$

Multiply the following expressions and represent them geometrically. $2\mathrm{x}\times 6$

Find the product of the following : $(\mathrm{x}+\mathrm{a})(\mathrm{x}+\mathrm{b})$

Find the product of the following : $(5\mathrm{x}-6\mathrm{y})(4\mathrm{x}-3\mathrm{y})$

Find the product of the following : $(\mathrm{x}-7)(\mathrm{x}+9)$

Find the product of the following : $(2\mathrm{x}+3)(\mathrm{x}+5)$