One dozen = 12
15/12 = 1.25
The cost of one fruit tart is $1.25
A and B are points on j.
C and D are points on k.
Join AD and BC.
ABCD is a quadrilateral.
Clearly, the quadrilateral ABCD is the only plane that contains the points A, B, C and D.
Hence, correct answer is option A. Exactly one.
If you're completing the square the answer is in the image.
expression
x^2 + 5x - 5=ax^2+bx+c
a=1, b=5, c=-5, and you can solve it that way.