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multiplying polynomials

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1 Answer

Hi Summyr;
(a-8)(a+5)
We are going to FOIL...
FIRST...(a)(a)=a2
OUTER...(a)(5)=5a
INNER...(-8)(a)=-8a---note the negative sign as the equation involves subtraction.
LAST...(-8)(5)=-40---note the negative sign as the equation involves subtraction.
 
a2+5a-8a-40
Let's combine like terms...
a2-3a-40
Note that the figure with the exponential, a2, comes first.  The figure with the coefficient, -3a, is second.  The constant, -40, is last.  This is standard hierarchy.