Question

find maximum value of x1^2+x2^2 where x1 and x2 are roots of quadratic equation x^2-kx+(k^2+7k+15)​

Answer 1

Step-by-step explanation:

Let x1 and x2 be the real root of the equation x2−kx+(k2+7k+15)=0, if the maximum value of (x21+x22)=18x, then find the value of x?

My attempt is as follows:-

x21+x22=(x1+x2)2−2x1x2

x21+x22=k2−2(k2+7k+15)

x21+x22=−k2−14k−30

Max value of x21+x22=−D4a

(x21+x22)max=196−1204

(x21+x22)max=19

hence 76=18x, x=1819. But actual answer is 1

Answer 2

download this app download Google meet