Which is a Quadratic ? A. 2x+3
B. 5x-7
C. x2+3x+12
D. x2+4x+12
E. x3+x2
F. 1/x
G. 5-x2

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lol

Step-by-step explanation:

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let's call the solutions x₁ = (5 - 2√7)/3 and x₂ = (5 + 2√7)/3

then the equation is (x-x₁)(x-x₂) = 0

if you fill that in you get a lot of numbers which you can recognize as ax²+bx+c=0.

step-by-step explanation:

you can see that a=1 (there is just an x²)

b = (-5 -2√7 + 2√7 - 5)/3 = -10/3

c = -2√7)/3 ) * (-5+2√7)/3) = -1/3

so your answer is 3x^2 – 10x – 1 = 0

236 cm 16 time 12 = 192

6 times 7 = 42

192+42