If the equation x^2−4x=k has at least one solution, which of the following must be true? Choose the correct choice from the following answers
A) k ≥−4 B) k < −9 C) k = 9 D) k ≤ 9 E) k ≥ −9
x^2−4x=k   =&gt; x^2−4x - k = 0   For a quadratic equation to have at least one solution, its discriminant (b^2-4ac) should be non-negative.   b^2-4ac ≥0   =&gt; 16 - 4*1*(-k) ≥0   =&gt; 16 + 4k ≥0   =&gt; k ≥ -4   k ≥−4nswer k ≥−4
<result>A</result>
If the equation x^2−4x=k has at least one solution, which of the following must be true?