8x + 12 = 4r - 16 find r
2 answers:
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Answer:
slope = - 1
Step-by-step explanation:
Calculate the slope m using the slope formula
m = (y₂ - y₁ ) / (x₂ - x₁ )
with (x₁, y₁ ) = (2, 0) and (x₂, y₂ ) = (- 6, 8)
m = =
= - 1
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