SOLUTION: find the product (9x-8)^2 a)81x^2+64 b)9x^2+64 c)9x^2-144x+64 d)81x^2-144x+64

Algebra ->  Equations -> SOLUTION: find the product (9x-8)^2 a)81x^2+64 b)9x^2+64 c)9x^2-144x+64 d)81x^2-144x+64      Log On


   

Question 147738: find the product
(9x-8)^2
a)81x^2+64
b)9x^2+64
c)9x^2-144x+64
d)81x^2-144x+64
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

%289x-8%29%5E2 Start with the given expression.


%289x-8%29%289x-8%29 Expand. Remember something like x%5E2=x%2Ax.


Now let's FOIL the expression.


Remember, when you FOIL an expression, you follow this procedure:


%28highlight%289x%29-8%29%28highlight%289x%29-8%29 Multiply the First terms:%289%2Ax%29%2A%289%2Ax%29=81%2Ax%5E2.


%28highlight%289x%29-8%29%289x%2Bhighlight%28-8%29%29 Multiply the Outer terms:%289%2Ax%29%2A%28-8%29=-72%2Ax.


%289x%2Bhighlight%28-8%29%29%28highlight%289x%29-8%29 Multiply the Inner terms:%28-8%29%2A%289%2Ax%29=-72%2Ax.


%289x%2Bhighlight%28-8%29%29%289x%2Bhighlight%28-8%29%29 Multiply the Last terms:%28-8%29%2A%28-8%29=64.


81%2Ax%5E2-72%2Ax-72%2Ax%2B64 Now collect every term to make a single expression.


81%2Ax%5E2-144%2Ax%2B64 Now combine like terms.


So %289x-8%29%5E2 FOILS to 81%2Ax%5E2-144%2Ax%2B64.


In other words, %289x-8%29%5E2=81%2Ax%5E2-144%2Ax%2B64.