Answer:
130° is the correct answer
∠QPR=80°
∠PQR+∠QPR+∠QRP=180°
∠PQR+∠QRP=100°
2(x+y)=100°
x+y=50°
So, in △QOR
x+y+∠QOR=180°
∴∠QOR=180°−50°
=130°
The maximum possible measurement is 1.25 Kg
and the minimum possible measurement is 1.15 kg
<u>Solution:</u>
Given mass of an ostrich egg is 1.2 Kg
We have to find the minimum and maximum possible measurements to the nearest tenth of a kilogram
The greatest possible error in measurement nearest tenth of a kilogram, is a half a tenth of a kilogram which is:-

Now, the maximum value will be equal to calculated amount plus the error in measurement of value .i.e.

Now, the minimum value will be equal to calculated amount minus the error in measurement of value .i.e.

Hence, maximum possible measurement is 1.25 Kg
And the minimum possible measurement is 1.15 kg
Answer: It is a difference of two squares, and it factors to (3x-7)(3x+7)
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Explanation:
We can write the 9x^2 as (3x)^2 since
(3x)^2 = (3x)*(3x) = (3*3)*(x*x) = 9x^2
The 49 can be written as 7^2 because 7^2 = 7*7 = 49.
This means 9x^2 - 49 is the same as (3x)^2 - 7^2. We have a difference of two squares.
The difference of squares factoring rule is
a^2 - b^2 = (a-b)(a+b)
which we have a = 3x and b = 7 in this case
So,
a^2 - b^2 = (a-b)(a+b)
(3x)^2 - 7^2 = (3x-7)(3x+7)
9x^2 - 49 = (3x-7)(3x+7)
Side note: This is the same as (3x+7)(3x-7). We can multiply two numbers in any order.