IMO E:govind_raj_76 wrote:What is the solution of the quadratic expression x^2 + bx + 16 ?
A) the two roots are equal.
B) b is odd.
Please explain how to solve this data sufficiency problem ?
Hi,govind_raj_76 wrote:What is the solution of the quadratic expression x^2 + bx + 16 ?
A) the two roots are equal.
B) b is odd.
Please explain how to solve this data sufficiency problem ?
I've already explained why this question isn't valid, but I just want to point out that if B is odd, assuming that we're solving for:aloneontheedge wrote:IMO E:govind_raj_76 wrote:What is the solution of the quadratic expression x^2 + bx + 16 ?
A) the two roots are equal.
B) b is odd.
Please explain how to solve this data sufficiency problem ?
stmtn 1 : If roots are equal b will have 2 values + or - 16
stmnt 2: If B is odd roots will be irrational
Stuart,Stuart Kovinsky wrote:Hi,govind_raj_76 wrote:What is the solution of the quadratic expression x^2 + bx + 16 ?
A) the two roots are equal.
B) b is odd.
Please explain how to solve this data sufficiency problem ?
there are two reasons why this is an invalid question - what's the source?
The first problem is that an expression doesn't have a "solution" - you can only solve an equation or inequality.
The second problem is that, even if we change the expression to the equation:
x^2 + bx + 16 = 0,
the two statements are contradictory - something that never happens on the actual GMAT.
If (1) is true, then x must be +4 or -4. If (2) is true, then x can be neither of those values, leaving us with no possible value for x. On the GMAT, there is always at least one value that satisfies both statements.
Hi,aloneontheedge wrote: If roots are equal discrimant wil be equal to zero.
using that we get b as +16 r - 16
Stmnt 2: i just plugged odd numbers and found them to be irrational
So chose E
Thanks stuart....i guess i just overlookedStuart Kovinsky wrote:Hi,aloneontheedge wrote: If roots are equal discrimant wil be equal to zero.
using that we get b as +16 r - 16
Stmnt 2: i just plugged odd numbers and found them to be irrational
So chose E
quadratic expressions don't have roots; only quadratic equations do - that's the primary reason why the question is invalid.
The secondary reason is that, as I outlined in my first post, the two statements have no common answers, something that will never happen on the GMAT.
