Write (-5 + 3a)2 as a trinomial

Question

Write (-5 + 3a)2 as a trinomial

 

 

Answer 1

everyone MUST learn that, in general, (x±y)² = x² ±2xy + y²  

which is fundamental to all of Algebra, which will be used over and over in your math classes, forever!

 

just substitute in this formula x = -5  and  y = 3a, and get

 

= 25 -30a +9a².

 

OBSERVE THAT THE MIDDLE TERM CONSISTS OF 2 TIMES THE x & y values (including their signs).