Q. 474.8( 9 Votes )
Solve for x and y:
, x + y = 2ab
⇒ b2x + a2y = a3b + ab3 …(i)
x + y = 2ab …(ii)
To solve these equations, we need to make one of the variables (in both the equations) have same coefficient.
Lets multiply equation (ii) by a2, so that variable y in both the equations have same coefficient.
Recalling equations (i) & (ii),
b2x + a2y = a3b + ab3
x + y = 2ab [×a2]
⇒ b2x – a2x = - a3b + ab3
⇒ (b2 – a2)x = ab(b2 – a2)
⇒ x = ab
Substitute x = ab in equations (i)/(ii), as per convenience of solving.
Thus, substituting in equation (ii), we get
(ab) + y = 2ab
⇒ y = ab
Hence, we have x = ab and y = ab.
Rate this question :
Solve the following pair of linear equation by cross - multiplication method:
x + 4y + 9 = 0
5x – 1 = 3yKC Sinha - Mathematics
Solve each of the following systems of equations by using the method of cross multiplication:
2x + y = 35, 3x + 4y = 65.RS Aggarwal - Mathematics
If 2x – 3y = 7 and (a + b) x – (a + b – 3) y = 4a + b represent coincident lines, then a and b satisfy the equationRD Sharma - Mathematics
A plane left 30 minutes later than the scheduled time and in order to reach the destination 1500 km away in time, it has to increase the speed by 250 km/hr from the usual speed. Find its usual speed.KC Sinha - Mathematics