[2x+9y=7],[(a+b)rc+(2a-b)y=21]

If the system of equations 2x+3y=7,\ \ \ \ (a+b)x+(2a-b)y=21 has infinitely many solutions, then

Find the values of a and b for which the following pair of equations have infinitely many solutions: (i) 2x + 3y = 7 and 2ax + ay =28-by (ii) 2x + 3y =7, (a-b) x + (a +b) y= 3a + b-2 (iii) 2x - (2a + 5) y =5, (2b +1) x - 9y =15

2x+3y=7(a+b)x+y(2a-b)=3(a+b+1) find the value of a+b

2x + 3y =7 , (a + b ) x + ( 2a - b ) y = 21 .

2x + 3y = 7& (a-b)x+ (a + b) y = 3a + b-2

Factorise the using the identity a ^(2) -b ^(2) = (a +b) (a-b). ( 4x ^(2))/(9) - ( 9y ^(2))/( 16)

2x + 3y = 7 , (a+b + 1 )x + (a + 2b + 2) y = 4 (a + b ) + 1

If (2y + 2z - x)/a = (2z + 2x - y)/b = (2x + 2y - z)/c ,then show that (9x)/(2b + 2c - a) = (9y)/(2c + 2a - b) = (9z)/(2a + 2b - c)

If the mean of 6,\ 7,\ x ,\ 8,\ y ,\ 14 is 9, then (a) x+y=21 (b) x+y=19 (c) x-y=19 (d) x-y=21

If the mean of 6,\ 7,\ x ,\ 8,\ y ,\ 14 is 9, then (a) x+y=21 (b) x+y=19 (c) x-y=19 (d) x-y=21