2 rational numbers are C. 2.777 and D. -7/3
a rational number<span> is any </span>number<span> that can be expressed as the quotient or fraction p/q of two integers
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as you know 0.7777 (7 repeat) = 7/9
so 2.777(7 repeat) = 2 7/9
45000 is the answer because 1800 x 25 = 45000
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Answer:</h2>
The quadratic function are:
option: A A) y(y + 4) - y = 6
Option: C C.) 4b(b) = 0
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Step-by-step explanation:</h2>
We know that the general equation of a quadratic equation in terms of a variable x is given by:

A)
y(y + 4) - y = 6
On simplifying the terms we have:

Hence, option: A is correct.
B)
(3x + 2) + (6x - 1) = 0

Hence, it is a linear equation.
Hence, option: B is incorrect.
C)
4b(b) = 0
it could also be written as:

Hence, it is a quadratic equation.
Hence, option: C is correct.
D)
3a - 7 = 2(7a - 3)

which is again a linear equation.
Hence, option: D is incorrect.
Carry out the mult.: f(x) = -[x^2 - 21x + 9x - 189]
Combine like terms: f(x) = -[x^2 - 12x - 189]
Eliminate the brackets [ ]: f(x) = -x^2 + 12x + 189
Identify coefficients a, b and c: a= -1, b=12, c=189
The equation of the axis of symmetry is x = -b/(2a), which here equals
x = -(12)/[2(-1)], or x = 6
This is also the x-coordinate of the vertex. Plug x=6 into the original equation to calculate the y-coordinate.