Intercepts and Graphs: Understanding the Use of 'OR' in Sketching Y=(x-2)(x-3)

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The discussion focuses on the mathematical reasoning behind using 'OR' when determining x-intercepts for the quadratic equation y=(x-2)(x-3). The x-intercepts are found by setting each factor to zero, resulting in x=2 and x=3. The use of 'OR' is justified because only one factor needs to be zero for the product to equal zero, illustrating the principle that if ab=0, either a or b must be zero, but not both simultaneously. This distinction is crucial for accurately sketching the graph of the equation.

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  • Explore the implications of using 'AND' vs 'OR' in mathematical expressions
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TyErd
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Alright let's says for example we were to sketch y=(x-2)(x-3). You would find x intercepts and you would write it as x-2=0 OR x-3=0, thus x=2 OR x=3. Why do we use the word OR when we use both of the intercepts to sketch the graph anyway? Why cannot we use AND instead.
 
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To find the x-intercepts, which is where y=0, when you have two variables multiplied together to equal zero, you only need one or the other to be 0.

e.g. if you have ab=0, where a and b are not equal, then a can be 0 or b can be 0, but since a is not equal to b then you can't have a and b are 0.

Same thing goes with that quadratic. (x-2)(x-3)=0 means that for some value x, the first factor (x-2) will equal zero while the second won't, and similarly for the second factor. This is why it is said x-2=0 OR x-3=0.
 

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