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Find the possible values of the constant
k, if the roots of the quadratic equation
x-(k+2)x+4=0 are equal.
8. If a and B are the roots of the quadratic
equation px' +qx+r=0, express
(2+a?)(2+B?) in terms p, q andr.
If y = 2x - 3x - 1, find the minimum
value of y and the corresponding value
ofx.
10. Given that y = 2 - 3x - 4x, find the
maximum value of y and the value of x
at which y is maximum.

pls answer no 7,9 and10​

Respuesta :

Step-by-step explanation:

7

x - (k+2)x + 4

Since the roots are equal, b^2 - 4ac =0

a =x, b=k+2, c =4

(k+2)^2 - 4(1×4) =0

K^2 + 4k + 4-16 =0

K^2 +4k - 12=0

K^2 +6k - 2k - 12 =0

K(k + 6) - 2(k +6)=0

(k-2)(k +6) =0

K =2 or - 6