1.

Draw the graph of the equation 3x-4y =12. comment on: (i)x=0, y=3 is a solution of the equation. (ii) The abscissa i.e. the value of x can never be 100 units. (iii) Sum of intercept (parts made by straight line on the axes) on the axed is 7 units. (iv) Length of line segment between the axes is 5 units (v) Area of triangle formed by the line 3x-4y =12 and co ordinate axes.

Answer»

Solution :We have
3x-4y =12
3x=4y+12
x=4y+12
3
Let y =0 `rArr` x=4
Let y = -3 `rArr` x= 0
Table for above values

Plot the points A(4,0) and B(0,-3) on the graph paper and join them . producer this line on both sides
(i)we see form the graph , that (0,3) does not lie on the given equation . so x=0 , y=3 is not the solution of
3x-4y=12
Also we can check algebraically (without seeing the graph)
putting x=0 and y =3 in 3x-4y=12 we get
3(0) - (3) =12
`rArr` -12=12 which is not true.
Spo , x =0,y =3 connot be the solution of given eqautio 3x-4y = 12
(ii) if we take any real value of x, then we get the corresponding value of y and vice versa from the equation 3x-4y =12 so x= 100 can also be taken
(iii) From the graph we see the intercept made by line on the y axis =-3
so sum of intercepts =4+(-3)=1
There , it is not true that sunm of inteceps is 7.
(iv) Since length of OA =4 units and length of OB =3 units `therefore` In RIGHT angle triangle AOB by pythagoras stheorem
`AB^(2)=OA^(2)+OB^(2)`
`=(4)^(2)+(3)^(2)=16+9=25`
`AB=sqrt(25)=5 units`
So length of line SEGMENT AB =5 units
(v) Area of triangle =`(1)/(2)xxOAxxOB=(1)/(2)xx4xx3` units
=6 sq units


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