Which one of the following options is true, and why ? 

$y=3 x+5$ has

$(i)$ a unique solution,

$(ii)$ only two solutions,

$(iii)$ infinitely many solutions

For each of the graphs given in Fig. select the equation whose graph it is from the choices given below :

$(a)$ For Fig. $(i)$,

$(i)$ $x+y=0$           $(ii)$ $y=2 x$            $(iii)$ $y=x$             $(iv)$ $y=2 x+1$

$(b)$ For Fig. $(ii)$,

$(i)$ $x+y=0$           $(ii)$ $y=2 x$            $(iii)$ $y=2x+4$             $(iv)$ $y=x-4$

$(c)$ For Fig. $(iii)$,

$(i)$ $x+y=0$           $(ii)$ $y=2 x$            $(iii)$ $y=2x+1$             $(iv)$ $y=2 x-4$

Give the geometric representations of $y = 3$ as an equation

$(i)$ in one variable

$(ii)$ in two variables

Find two solutions for each of the following equations :

$(i)$ $4 x+3 y=12$

$(ii)$ $2 x+5 y=0$

$(iii)$ $3 y+4=0$

If the work done by a body on application of a constant force is directly proportional to the distance travelled by the body, express this in the form of an equation in two variables and draw the graph of the same by taking the constant force as $5$ units. Also read from the graph the work done when the distance travelled by the body is

$(i)$ $2$ units

$(ii)$ $0$ units

You know that the force applied on a body is directly proportional to the acceleration produced in the body. Write an equation to express this situation and plot the graph of the equation.