Answer:
12 30
Step-by-step explanation:
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
The word "associative" comes from "associate" or "group";the Associative Property is the rule that refers to grouping. For addition, the rule is "<span>a + (b + c) = (a + b) + c</span><span>"; in numbers, this means
</span>2 + (3 + 4) = (2 + 3) + 4. For multiplication, the rule is "<span>a(bc) = (ab)c</span>"; in numbers, this means2(3×4) = (2×3)4<span>. Any time they refer to the Associative Property, they want you to regroup things; any time a computation depends on things being regrouped, they want you to say that the computation uses the Associative Property.</span>
