Answer this and add work, show all work for math. : p

Lines are in the form y=mx+b, where m is the slope and b is the y-intercept.  This line is thus y=9/4x-14, so C is correct.  Multiplying by four, we get 4y=9x-56.  Adding 56 and subtracting 4y, we see that 9x-4y=56, and multiplying by -1, we get 4y-9x=-56, so A is also correct.  At this point, it is clear that B and D are incorrect, so A and C only are correct.

You know that you can spot the slope and intercept right away
IF you 'solve' the equation for 'y'.  Then you'll have

                                y = (slope) x  +  (intercept) .

So for choices 'A' and 'B', you have to massage the equation
into the standard form, and then just look at it and see whether
the slope is 9/4 and the intercept is -14.

A).                             -9x + 4y  =         -56

Add 9x to each side:        4y = 9x    - 56

Divide each side by 4 :     y = 9/4 x - 14            <== Yes !  Good one.

B).                                       9x + 4y =            56

Subtract  9x from each side:   4y = -9x   + 56

Divide each side by  4 :             y = -9/4 + 14   <= no, signs are wrong

C).  Yes.  Slope is 9/4 and intercept is -14 . 

D).  No.  Slope is 9/4 alright, but intercept is +14, not -14 .

No solution : there is no number of boxes that she bought