Conditions for Common Roots

IMPORTANT

Conditions for Common Roots: Overview

This topic covers concepts such as Condition for the Common Roots, Quadratic Equations with Both Roots Common, Quadratic Equations with Exactly One Common Root, and Common Root of Two Quadratic Equations.

Important Questions on Conditions for Common Roots

MEDIUM
IMPORTANT

If the equations x2-11x+k=0 and  x2-14x+2k=0 have a common root, find the sum of possible values of k.

MEDIUM
IMPORTANT

If one root of the equations ax2+bx+c=0 and bx2+cx+a=0a, b, cR is common, then find the value of a3+b3+c3abc3

HARD
IMPORTANT

If x2+3x+5=0 and ax2+bx+c=0 have common root / roots and a, b, cN. then the minimum value of a+b+c is 

MEDIUM
IMPORTANT

If all the equations x2+(2a+3b)x+60=0, x2+ax+10=0 and x2+bx+8=0 where a, bR, have a common root, then value of |a-b| is

MEDIUM
IMPORTANT

If the equation x2+px+2q=0 and x2+qx+2p=0(pq) have a common root
then the absolute value of (p+q) is

MEDIUM
IMPORTANT

If all the equations x2+(2a+3b)x+60=0,x2+ax+10=0 and x2+bx+8=0 where a,bR,have a common root, then value of |a-b| is

HARD
IMPORTANT

If bx2+ax+c=0, ax2+bx+c=0 and ax2+cx+b=0, each equation has equal roots, then 3abc3bac3cab is equal to

HARD
IMPORTANT

For next two question please follow the same  

 If the quadratic equations a1x2 + b1x + c1 = 0 and a2x2 + b2x + c2 = 0 have exactly one common root, then the relation between their coefficients is c 1 a 2 - c 2 a 1 2 = b 1 c 2 - b 2 c 1 a 1 b 2 - a 2 b 1 . If both the roots are common, then the relation between their coefficient is  a 1 a 2 = b 1 b 2 = c 1 c 2 .

 If the equations ax3+3bx2+3cx+d=0 and  ax2+2bx+c=0  have a common root, then which of the following option is correct ?

HARD
IMPORTANT

If equations x2+ax+b=0(a,bR) & x3+3x2+5x+3=0 have two common roots, then value of 2ba is equal to

MEDIUM
IMPORTANT

If the quadratic equations ax2+2bx+3c=0 and 3x2+8x+15=0 have a common root (where a,b,c are the lengths of sides of a ABC), then sin2A +sin2B+sin2C=_____ 

MEDIUM
IMPORTANT

If the quadratic equations ax2+bx+c=0  and bx2+cx+a=0 have a common root, (where a0 ) then a3+b3+c3abc=____

HARD
IMPORTANT

If a, b, c are in A.P. and if b-cx2+c-ax+a-b=0 and 2c+ax2+b+cx=0 have common root then which one is correct

HARD
IMPORTANT

Consider the cubic equation: 2ax3+bx2+cx+d=0 and quadratic equation 2ax2+3bx+4c=0 having a common root and λbc+ad2=92μbd+4c2mb2-nac then the value of the expression λ+μ+m+n is

MEDIUM
IMPORTANT

If equations ax2+bx+c=0; a, b, cR & c0 and 2x2+3x+4=0 have a common root, then a:b:c equals 

MEDIUM
IMPORTANT

If the quadratic equations k6x2+3+rx+2x2-1=0 and  6k2x2+1+px+4x2-2=0 have both the roots common, then  2r-p is equal to

MEDIUM
IMPORTANT

If the equations ax2+2bx+c=0 and dx2+2ex+f=0 have a common root and a, b and c are in geometric progression, then da, eb, fc are in:

EASY
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If quadratic equations x2-bx+c=0 and x2-cx+b=0 and bc have a common root then b+c-3 is equal to

HARD
IMPORTANT

If the equations 2x2-7x+9=0 and ax2+bx+18=0 have a common root, then a,bR

HARD
IMPORTANT

The quadratic equations x2-6x+a=0 and x2-cx+6=0 have one root in common. The other roots of the first equation and the second equation are integers in the ratio 4:3. Then the common root is

MEDIUM
IMPORTANT

The equations kx2+x+k=0 and kx2+kx+1=0 have exactly one root in common for