MaxWong

The system is equivalent to $\begin{cases} 2x + ky &=& 9\\ kx + 3y &=& 13 \end{cases}$.

As long as the lines represented by the equations are not parallel, the system would have a unique solution.

$-\dfrac2k \neq -\dfrac k3\\ k^2 \neq 6\\ k \neq \pm \sqrt 6$

For $k \neq \sqrt 6$ and $k \neq -\sqrt 6$, the system has a unique solution.

P.S. You need to convert it to inches per second.

Yes, your answers are correct.

The factored polynomial is of the form $(ax + b)(cx + d)$. Since 13 and 17 are primes, either a or c is 13, and either b or d is 17 or -17.

Listing all possibilities:

$\begin{array}{rcl} (13x - 1)(x + 17) &=& 13x^2 + 220x - 17\\ (13x + 1)(x - 17) &=& 13x^2 -220x - 17\\ (13x + 17)(x - 1) &=& 13x^2 + 4x - 17\\ (13x - 17)(x + 1) &=& 13x^2 - 4x - 17 \end{array}$

The possible values of n are -220, -4, 4, 220.

Let a be the number of badges Aaron has, b be the number of badges Ben has, and c be the number of badge Calvin has.

Then, $\begin{cases} a &=& \dfrac34 b\\ b &=& \dfrac25 c\\ a &=& b - 8 \end{cases}$

Plugging in the first equation into the third equation gives $\dfrac34b = b - 8$. Solving gives b = 32.

Can you take it from here? You can calculate the value of c and calculate c - b to be the answer.

But are the coordinates of A given?

The maximum of f(x) + g(x) is always not greater than the maximum of f(x) + the maximum of g(x) because if the maximum point of f(x) and the maximum of g(x) point is not aligned on a vertical line, the maximum of f(x) + g(x) is going to be smaller.

That means, $\max(f(x) + g(x)) = b \leq \max(f(x)) + \max(g(x)) = 3 + 1 = 4$.

Then $b \leq 4$.

It would be nice if the function keeps being 3x^2 + 2 throughout.

Since the graph of y = 3x^2 + 2 is a parabola, we know that it is continuous.

Then a = 3 is the answer.

Alternative solution:

Since we know the roots are a and b, we know that $7x^2 + x - 5 = 7(x - a)(x - b)$.

Expanding the right-hand side gives $7x^2 + x - 5 = 7x^2 - 7(a + b)x + 7ab$.

Comparing the coefficients of x on both sides: $1 = -7(a + b)$.

Therefore, $a + b = -\dfrac17$.

Now, $(a - 4) + (b - 4) = (a + b) - 8$, using this gives $(a - 4) + (b - 4) = -\dfrac17 - 8 =\boxed{ -\dfrac{57}8}$.

It's okay, we were writing our responses at the same time.