If the equations `x^2+ax+12=0`,`x^2+bx+15=0` and `x^2+(a+b)x+36=0` have a common root , then which is true

If the equation x^2+ax+12=0 , x^2 +bx +15 =0 and x^2 +(a+ b) x+ 36 =0 have a common positive root, then b- 2a is equal to

If the equation x^(2)+ax+12=0,x^(2)+bx+15=0 and x^(2)(a+b)x+36=0 have a common positive root,then b-2a is equal to

If the equations x^(2) - ax + b = 0 and x^(2) + bx - a = 0 have a common root, then

IF x^2 +ax+bc=0 and x^2+bx +ca=0 have a common root , then a + b+ c=

If the equations x^(2)+ax+12=0,x^(2)+bx+15=0 and x^(2)+(a+b)x+36=0 have a common positive root, then the ordered pair (a, b) is

If the equation ax^(2) + bx + c = 0 and 2x^(2) + 3x + 4 = 0 have a common root, then a : b : c

If the equation ax^(2) + bx + c = 0 and 2x^(2) + 3x + 4 = 0 have a common root, then a : b : c

If the equations x^2 + 2x + 3 = 0 and ax^2 + bx + + c = 0 have common root, then a : b : c is _____