The correct option is b.
<h2>Quadratic Equation</h2>A quadratic equation is an equation that can be written in the form of
ax²+bx+c.
Where a is the leading coefficient, and
c is the constant.
<h2>Leading coefficient </h2>The leading coefficient of an equation is a coefficient of the term having the highest power in the equation.
Given options:
a.)
b.)
c.)
d.)
As it is given that the leading coefficient of the equation is 3. therefore, the value of the 'a' in the general quadratic equation is 3,
3x²+bx+c,
Also, the value of the constant is -12, therefore, the value of c is -12,
3x²+bx-12
From all the given options the only feasible option is b only.
Hence, the correct option is b.
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