Comparing the equation $x=4$ with the standard form $ax+by+c=0$,we get $b=\ldots \ldots \ldots$

Obtain a pair of linear equations in two variables from the following information: Three years ago,the age of Abhishek was four times the age of Sweta. After five years,the age of Abhishek will be two times the age of Sweta.

Solve the following pair of linear equations: $2(3u - v) = 5uv$ and $2(u + 3v) = 5uv$.

The solution of the pair of equations $x + 2y = 5$ and $2x + y = 4$ is .........

Vijay had some bananas,and he divided them into two lots $A$ and $B$. He sold the first lot at the rate of $Rs. 2$ for $3$ bananas and the second lot at the rate of $Rs. 1$ per banana,and got a total of $Rs. 400$. If he had sold the first lot at the rate of $Rs. 1$ per banana,and the second lot at the rate of $Rs. 4$ for $5$ bananas,his total collection would have been $Rs. 460$. Find the total number of bananas he had.

In the pair of equations $a_{1}x + b_{1}y + c_{1} = 0$ and $a_{2}x + b_{2}y + c_{2} = 0$,if $\ldots \ldots \ldots \ldots$ then there is no solution (the solution set is an empty set).