The slope of AC is -0.4
Proof:
In triangles ABC and DBE,
∠DBE is common to both triangles.
AB = 2DB (D is the midpoint of the interval AB)
Also, BC = 2BE (E is the midpoint of the interval BC)
Thus triangles ABC and DBE are similar in the ratio 2:1
Since, they are similar, ∠BDE must equal ∠BAC (corresponding angles in similar triangles)
If ∠BDE = ∠BAC, DE must be parallel to AC (corresponding angles are equal along parallel lines)
Thus, the slope of AC = the slope of DE
Thus, the slope of AC is -0.4
The system:
- 12 c + 3 d = 6
- 3 c + 6 d = - 9
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The 1st equation:
- 12 c = - 3 d + 6 / * ( - 1) ( multiple both sides by -1 )
12 c = 3 d - 6 / : 12 ( divide both sides by 12 )
c = d / 4 - 1/2
Answer:
C ) c = 1/4 d - 1/2
I’m pretty sure it should be ,B
The answers is A !! No problem