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25 votes
25 votes
Put the following equation in standard form and determine the quadratic, linear, and constant coefficients. -3x2 - 8 = 5x - 7

User Richard Grimshaw
by
2.8k points

1 Answer

18 votes
18 votes

Answer:

  • -3x² -5x -1 = 0
  • -3 (quadratic)
  • -5 (linear)
  • -1 (constant)

Explanation:

The equation will be in standard form when terms are listed in order of decreasing degree, and the right side of the equation is 0.

Standard form

We can subtract the right-side expression from both sides to get standard form.

-3x² -8 -(5x -7) = 5x -7 -(5x -7)

-3x² -8 -5x +7 = 0 . . . . . . . simplify a bit

-3x² -5x -1 = 0 . . . . . . . . . collect terms

The standard form equation can be written ...

-3x² -5x -1 = 0

Coefficients

The quadratic coefficient is the coefficient of the term with degree 2. The quadratic coefficient is -3.

The linear coefficient is the coefficient of the term with degree 1. The linear coefficient is -5.

The constant coefficient is the coefficient of the term with no variables. The constant is -1.

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Additional comment

We can make the leading coefficient positive by multiplying the equation by -1. This gives ...

3x² +5x +1 = 0

with quadratic, linear, and constant coefficients 3, 5, 1.

This is a legitimate answer to this question. In the case of linear equations, the "standard form" has the constant on the right side of the equal sign, and the leading coefficient is required to be positive. A negative leading coefficient can sometimes lead to errors (when the sign is overlooked), so having a positive leading coefficient is often preferred.

User Ganjeii
by
2.7k points
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