Question 114811
If we graph {{{y=2x^2+5x-3}}}, we get


{{{ graph( 500, 500, -10, 10, -10, 10, 2x^2+5x-3) }}}


which fails the horizontal line test. So the function is not one-to-one


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If we graph {{{y=abs(x-2)}}}, we get


{{{ graph( 500, 500, -10, 10, -10, 10, abs(x-2)) }}}


which fails the horizontal line test. So the function is not one-to-one



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Remember, {{{y=x^(-1/2)}}} is the same as {{{y=sqrt(x)}}}


If we graph {{{y=sqrt(x)}}}, we get


{{{ graph( 500, 500, -10, 10, -10, 10, sqrt(x)) }}}


which passes the horizontal line test. So the function is one-to-one