(iv)
x
2
+
2y
3
and
x
y
3
–
- 3
= 0
Soln.
Elimination method
x
2
+
2y
3
=
-1
Multiplying throughout by 6 in eq (i), we get
3x
+
4y
=
-6
... (i)
x
y
3
–
=
3
Multiplying throughout by 3 in eq (ii), we get
3x
–
y
=
9
Subtracting eqn (iv) from eqn (iii)
... (ii)
3x
+
4y
=
-6
... (iii)
3x
–
y
=
9
... (iv)
–
+
–
5y
=
-15
y
=
-15
5
y
=
-3
Substituting y = – 3 in eqn (iii), we get
3x
+
4(-3)
=
-6
3x
–
12
=
-6
3x
=
-6
+
12
3x
=
6
x
=
2
Solution is x = 2, y = – 3
+1 = 0
To remove ‘2’ & ‘3’ from denominator multiply by LCM of 2 & 3
LCM of 2 & 3 is 6
To remove ‘3’ from denominator multiply by LCM of 3
LCM of 3 is 3
... (iii)
... (iv)
Are the Coefficient of X is same
Yes !!
Are the Coefficient of Y is same
No !!
1
3x
+
4y
=
-6
... (iii)
Now which two
equations have
to be solved ??
equations (iii) & (iv)…
+
+
x
=
6
3
2
Constant → R.H.S.
− 12 → 12
In eliminition method, keep variable on L.H.S and constant on R.H.S
How to get the value of ‘x’ ?
Either equation (iii) or equation (iv)
We need to either remove x or remove y
Which variable can be removed ?
Whichever variable’s coefficient is same
Here coefficent of
x is same
To remove x, we need to subtract
As Signs are same
Number the equation as equation (iii)
Number the equation as equation (iv)