Helping students gain understanding and self-confidence in algebra.
zachres wrote:I ran across this yesterday in a Pearson intermediate Algebra text.
The problem presented in the text is in regards to graphing ordered pairs. An equation to express the relationship between the pair is given as;
y = 4 - x2
The solution requested is a graph x and y for all pairs where x is an integer from -3 to 3.
For x = -3, the author of the book substituted in this manner;
y = 4 - (-3)2
My question is; why would the substitution not be in this form; y = 4 - (-32)?
The two methods generate different values for x2. The first generates 9, and the second generates -9.
So, again, why one way and not the other?