Given the following question:
First expression:

Second expression:
Answer:
Step-by-step explanation:
The sum of the angles of a triangle is always 180°.
(2x+4) + (2x-2) + (x-2) = 180
5x = 180
x = 36°
The answer to <span>-7(k+9)=9(k-5)-14k is
k = -9
</span>-7(k+9)=9(k-5)-14k
Use the distributive property to distribute the -7 to (k+9) and 9 to (k-5)
-7(k+9)=9(k-5)-14k
-7k - 63 = 9k - 45 - 14k
Now lets get all our constants on one side of the equal sign and all our terms such as 9k and 4k on a side by their self
-7k - 63 = 9k - 45 - 14k
-7k - 63 + 45 = 9k - 45 + 45 - 14k
-7k - 18 = 9k - 14k
Now lets get that -7k on the right side
-7k + 7k - 18 = 9k - 14k + 7k
-18 = 9k - 14k + 7k
Now lets do the math for 9k - 14k + 7k and solve for k
-18 = 9k - 14k + 7k
-18 = 2k
-18 / 2 = 2k / 2
-9 = k
k = -9

is the formula for calculating x1 and x2
To prove x1 + x2 = -b/a all we need to do is to express x1 and x2 from equation above
once we do we will get -2b/2a which is equal to -b/a because square root part will negate each other. one has + sign in front and other - sign
Showing that x1x2 = c/a goes similar way.
the numerator parts is actually difference of squares. after that we will have:
-b^2 -b^2 + 4ac = 4ac
in denominator we have 2a*2a = 4a^2
4ac/4aa = c/a
Answer:

Step-by-step explanation:
=
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Hope this helped! <3