The expression 1/3x^2 - 2 can be rewritten as 1/3 (x - k) (x + k) , where k is a positive constant. What is the value of k ?

The correct answer is D. Choice D is correct. Factoring out the coefficient 1/3 , the given expression can be rewritten as 1/3 (x^2 - 6) . The expression x^2 - 6 can be approached as a difference of squares and rewritten as (x - sqrt(6)) (x + sqrt(6)) . Therefore, k must be sqrt(6) .

Note: The regression fits the positive k as 2.44948974278, which matches √6.

Holy trap. In order to factor out 1/3 as the leading coefficient, we first have to perform: c 1/3 = 2. Therefore c = 6. Then we can perform difference of squares and get: 1/3 (x - sqrt6) (x+ sqrt6) tricky.

SAT Question a0b4103e: Answer, Explanation & Desmos Solution

The expression $\frac{1}{3} x^{2} - 2$ can be rewritten as $\frac{1}{3} (x - k) (x + k)$ , where $k$ is a positive constant. What is the value of $k$ ?

Difficulty:Hard

$2$

$6$

$2$

$6$

Explanation

Enter in Desmos:

Why the other choices are wrong

Student discussion

SAT Question a0b4103e: Equivalent Expressions answer and explanation with Desmos solution

Explanation

Enter in Desmos:

Why the other choices are wrong

Student discussion