To solve the given question regarding the highest degree of an equation that can efficiently use the quadratic formula, let's analyze each option.
The quadratic formula is a standardized method for solving quadratic equations, which are polynomial equations of the second degree, typically in the form:
[tex]\[ ax^2 + bx + c = 0 \][/tex]
where [tex]\(a\)[/tex], [tex]\(b\)[/tex], and [tex]\(c\)[/tex] are coefficients, and [tex]\(a \neq 0\)[/tex].
Let's examine the options:
A. If the highest degree in the equation is 2, this fits perfectly with the quadratic formula's form [tex]\( ax^2 + bx + c = 0 \)[/tex].
B. If the highest degree in the equation is 0, this represents a constant equation (e.g., [tex]\( c = 0 \)[/tex]), which does not have any variable and thus doesn't require solving using the quadratic formula.
C. If the highest degree in the equation is 1, this represents a linear equation (e.g., [tex]\( bx + c = 0 \)[/tex]). Linear equations do not need the quadratic formula; they can be solved using simple algebraic methods.
D. If the highest degree in the equation is 3, this represents a cubic equation, which cannot be solved using the quadratic formula as it requires different techniques beyond quadratic scope, or even potentially more complex mathematical methods.
From this analysis, we conclude that the highest degree in an equation that can be solved using the quadratic formula is:
[tex]\[ \boxed{2} \][/tex]
Therefore, the correct answer is:
A. 2
