Question
A student factored $4 y^{2}-10 y+4$ as $(2 y-1)(2 y-4)$ on her factoring test. Why did her professor deduct several points, even though $(2 y-1)(2 y-4)$ does multiply out to $4 y^{2}-10 y+4 ?$
Step 1
We can do this by multiplying the factors together. \[ (2y - 1)(2y - 4) = 4y^2 - 8y - 2y + 4 = 4y^2 - 10y + 4 \] This is the same as the original expression, so the student's factorization is correct in that sense. Show more…
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