maths identity problem?

(3x + c ) ( x + c) = 3x^2 - dx + 16

3x² + (4c)x + c² = 3x² - dx + 16

Because corressponding parts of corresponding terms are equal.

c² = 16

c = ± 4

4c = -d

when c = 4

4(4) = -d

d = -16

when c = -4

4(-4) = -d

d = 16

(c, d) = (-4, 16), (4, -16)

I hope this helps!

open the brackets thus, 3x^2 + 4xc + c^2 = 3x^2 - dx +16

compare coefficients, coefficient of x^2 is 3 on both sides.

coefficient of x, 4c = -d ie d= -4c

constant term c^2 = 16 so c = +4 or -4

c=4 and d= -16

or c= -4 and d=16

c= -4 is more logical

thus d has positive value

d= -4c = 16

{c=-4, d=16}

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