12 : 19...................
<h2>Greetings!</h2><h3>When expanding brackets, you simply multiply whatever is inside the brackets by what is outside:</h3>

<h3>Which would result in the answer being:</h3>

<h2>Hope this helps!</h2>
Answer:
Incident ray, the reflection ray and the normal to thereflection surface at the point of the incidence lie in the same plane
Answer:
-69x-66
Step-by-step explanation:
1) given: a₁=-4x-1; a₂=-9x-6; a₃=-14x-11. Find: a₁₄-?
2) a₁₄=a₁+13d, where d - the difference between neighbor-terms;
3) d=a₂-a₁; ⇔ d= -9x-6+4x+1= -5x-5;
4) a₁₄= -4x-1+13*(-5x-5)= -69x-66.