Find a,b, and c: x squared minus twenty-five.

Question

The title tells it all. Find a,b, and c: x^2-25

Answer 1

When working with quadratics, the usual formula for working with them is as a trinomial where ax²+bx+c=0. The 'a' 'b' and 'c' are simply coefficients that may or may not be in the formula.

If there is no number in front of one or the other of the variables, then the coefficient is assumed to be '1'. The 'c' term is the positive or negative number at the end of the trinomial. If there is not a middle term, 'b', then the coefficient MUST be zero, and it is eliminated from the trinomial.

 

Is this enough information? Please let me know if it isn't. Thanks!

Answer 2

A quadratic equation (an equation with an x² in it) in standard form is written ax² + bx + c= 0 (given that "a" does NOT equal zero - if it did, it wouldn't be a quadratic). This form works because it makes it easy to plug an equation into the quadratic formula. (Quadratic equation... quadratic formula...). The lack of an equal sign just makes this a quadratic expression. However, you keep the same form. Therefore, a is the coefficient of your x² term, b is the coefficient of your x term, and c is your constant (or your number).

 

In this equation:

• There is an implied 1 in front of the x². (Any thing times 1 = itself)
• There is an implied 0 in front of the x. Any thing times 0 = 0.
• Your constant is 25. This is the easy one.

 

Therefore

• a=1, b=0, c=25

 

Enjoy your studying, Mr. Brendan!

Kyle J. Smith