Answers

2014-08-11T21:18:35+05:30
Lets say the expression is of the form (x^{2} + bx + c) ^{2}
Expand it -> x^{4} + 2b x^{3} + ( b^{2} + 2c) x^{2} + 2bcx +  c^{2}

Now compare the coefficients
2b = 8 -> b = 4
b^{2} + 2c = -7 -> c = - \frac{11}{2}

Now,
k = 2bc -> k = -22
l = c^{2} -> l = \frac{121}{4}
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