If a.b = M, M is different from 0 and (a+b) = 4, then :
a. there are always real values for a,b
b. whenever 4>= M >0 there are real values for a,b
c. whenever 0> M there are positive values for both a,b
d. whenever 0>M there are negative values for both a,b
a and b can be considered as the roots of the following quadratic equation:
x^2 -(a+b)x+ab=0,so for real values of a and b,,(-(a+b))^2-4*ab>or =0,, (-4)^2-4M>=0,,,,,M<=4,,,, but M cant be zero as ab is non zero,,,
but i dont see anything wrong in M being less than o,,, but since that option is nt given,,, so i think option b shud be taken,, whats d answer by the way?
Locked
