standard_description: Add and subtract fractions with unlike denominators (including mixed numbers) by replacing given fractions with equivalent fractions in such a way as to produce an equivalent sum or difference of fractions with like denominators. For example, 2/3 + 5/4 = 8/12 + 15/12 = 23/12. (In general, a/b + c/d = (ad + bc)/bd.)
problem_activity: What is the minimum value taken by the expression
$${{{(x-}}4)^2+6}$$
? How does the structure of the expression help to see why?
Rewrite the quadratic expression
$${ x^2-6x-3}$$
in the form
$${{(x-}}$$
_____
$${{ )^2+}}$$
______ .
Rewrite the quadratic expression
$${-2x^2+4x+3}$$
in the form  ____
$${{(x-}}$$
_____
$${{ )^2+}}$$
______ .


aligns: no