An equation for the parabola would be y²=-19x.
Since we have x=4.75 for the directrix, this tells us that the parabola's axis of symmetry runs parallel to the x-axis. This means we will use the standard form
(y-k)²=4p(x-h), where (h, k) is the vertex, (h+p, k) is the focus and x=h-p is the directrix.
Beginning with the directrix:
x=h-p=4.75
h-p=4.75
Since the vertex is at (0, 0), this means h=0 and k=0:
0-p=4.75
-p=4.75
p=-4.75
Substituting this into the standard form as well as our values for h and k we have:
(y-0)²=4(-4.75)(x-0)
y²=-19x
You have the ratios set up but you need to cross multiply everything:
(5x + 10) x 11 = 121 x 10
55x + 110 = 1210
Subtract 110 from both sides:
55x = 1100
Divide both sides by 55:
X = 1100 / 55
X = 20
P ⇒ Parenthesis
E ⇒ Exponents
M ⇒ Multiplication
D ⇒ Division
A ⇒ Addition
S ⇒Subtraction
Here is how I was taught to remember all the letters. (Please Excuse My Dear Aunt Sally)
Answer: 18
Step-by-step explanation:
1282 divided by 65 = 19 R 47
65 - 47=18
