How do I solve this problem?

Step-by-step explanation:

Use this formula,

where n is the amount of even intergers, a is the starting term, d is the common difference.

i think c. but don't trust it.

step-by-step explanation:

answer:   x = 3 + √11     and     x = 3 - √11

step-by-step explanation:

x² - 6x + 9 = 11

(x - 3)² = 11

x - 3 = ±√11

    x = 3 ± √11

x = 3 + √11     and     x = 3 - √11