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michael0195
Identify the domain and range for the graph of y = −2x2 − 8x + 1
domain for all polynomials is all real numbers! :) now the best thing to do is put this into this form \[y=a(x-h)^2+k \] to find the range This form is called vertex form by the way!
or i guess you could look at visually but i don't care for that
\[y=-2(x^2+4x)+1\] \[y=-2(x^2+4x+(\frac{4}{2})^2)+1+2(\frac{4}{2})^2\] Notice I added in a[b/2]^2 So I had to take it out! :) Now we have \[y=-2(x+2)^2+1+2(\frac{16}{4})=-2(x+2)^2+1+8\] \[y=-2(x+2)^2+9\] I see that the vertex is (-2,9) |dw:1331078112680:dw| That means the range is \[[-\infty,9]\] Luis feedback group