Answer:
Step-by-step explanation:
focus (1 , -7) ⇒ a = 1 & b = -7
y = 1 ⇒ c = 1
Equation of parabola :
(x - a)² + (y - b)² = (y - c)²
(X - 1)² + (y + 7)² = (y - 1)²
Now, expand.
x² - 2x + 1 + y² + 2*7*y + 7² = y² - 2*y*1 + 1
x² - 2x + 1 + y² - 14y + 49 = y² - 2y +1
x² - 2x + 1 + y² - 14y + 49 - y² + 2y - 1 = 0
x² - 2x + <u>y² - y²</u> <u> - 14y + 2y</u> <u>+ 1 + 49 - 1 </u>= 0
x² - 2x - 12y + 49 = 0
Length of the model on the bottom = (5 x 18) / 3 = 30 cm
Answer:

Step-by-step explanation:
Here we are going to apply the rule of "Square of the difference". The rule is as given below
---------(A)
Now we have our original polynomial as

Which can be re written as
---------------(B)
Hence comparing it with (A)

Applying the rule on (B)

Hence our answer is

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