What is the slope of the line that passes through the points (-8,3)
1 answer:
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Answer:
x = - 4 ± 2
Step-by-step explanation:
Given
f(x) = x² + 8x + 4
To find the zeros let f(x) = 0, that is
x² + 8x + 4 = 0 ( subtract 4 from both sides )
x² + 8x = - 4
To solve using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(4)x + 16 = - 4 + 16
(x + 4)² = 12 ( take the square root of both sides )
x + 4 = ± = ± 2
( subtract 4 from both sides )
x = - 4 ± 2
Thus the zeros are
x = - 4 - 2 and x = - 4 + 2
Answer:
Step-by-step explanation:
They wanted to complete the square so they took the thing in front of x and divided by 2 then squared. Whatever you add in, you must take out.
Now we are read to write that one part (the first three terms together) as a square:
I don't see this but what happens if we find a common denominator for those 2 terms after the square. (b/2a)^2=b^2/4a^2 so we need to multiply that one fraction by 4a/4a.
They put it in ( )
I'm going to go ahead and combine those fractions now:
I'm going to factor out a -1 in the second term ( the one in the second ( ) ):
Now I'm going to add (b^2-4ac)/(4a^2) on both sides:
I'm going to square root both sides to rid of the square on the x+b/(2a) part:
Now subtract b/(2a) on both sides:
Combine the fractions (they have the same denominator):