Answer:
0
Explanation:
To find the value of an expression for specific values of the variable, substitute those values for the variable and do the arithmetic.
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at x=r1
y = (r1 -r1)(r1 -r2) = 0×(r1 -r2)
y = 0
at x=r2
y = (r2 -r1)(r2 -r2) = (r2 -r1)×0
y = 0
The value of y at x=r1 and x=r2 is 0.
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Additional comment
The values r1 and r2 are called the "zeros" of the function y, because the value of the function is zero there. These values can be seen to be the opposites of the constants in the factors of y. (r1 is the opposite of -r1 in the first factor, for example.)