A, B, and D are the correct answers
We can consider that the runner did an acceleration of 0.8 m.s during the 10 seconds of difference.
We can deduce that the runner did an acceleration of 0.08 m.s every second during this time.
If the angles of a triangle form an arithmetic sequence, the middle angle must be the average of the three angles, hence 180°/3 = 60°. The sum of the other two is then 180° -60° = 120°
The largest angle is 120° - 23° = 97°.
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The common difference is 37°.
(7x2+x+9)-(3x2+4x-5)
4x2-3x+4 is your answer (: