Answer:
96
Step-by-step explanation:
commom difference = d
a₆ + a₇ = 16
a₅ + a₈ = (a₆ - d) + (a₇ + d) = a₆ + a₇ = 16
a₄ + a₉ = (a₆ - 2d) + (a₇ + 2d) = a₆ + a₇ = 16
Similarly,
a₃ + a₁₀ = 16, a₂ + a₁₁ = 16, a₁ + a₁₂ = 16
so
a₁ + a₂ + ... + a₁₁ + a₁₂ = 6 x 16 = 96
Find the vertex by using the formula -b/2a
To find a and b, we must know that a and b are located at y = ax^2 + bx + c.
We find that b is 4 and a is 1 by looking at the given quadratic function.
The answer is A. -4/2(1) because the question is looking for the correct steps to find the answer.
