Question 147739


{{{(10+7x)^2}}} Start with the given expression.



{{{(10+7x)(10+7x)}}} Expand. Remember something like {{{x^2=x*x}}}.



Now let's FOIL the expression.



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



{{{(highlight(10)+7x)(highlight(10)+7x)}}} Multiply the <font color="red">F</font>irst terms:{{{(10)*(10)=100}}}.



{{{(highlight(10)+7x)(10+highlight(7x))}}} Multiply the <font color="red">O</font>uter terms:{{{(10)*(7*x)=70*x}}}.



{{{(10+highlight(7x))(highlight(10)+7x)}}} Multiply the <font color="red">I</font>nner terms:{{{(7*x)*(10)=70*x}}}.



{{{(10+highlight(7x))(10+highlight(7x))}}} Multiply the <font color="red">L</font>ast terms:{{{(7*x)*(7*x)=49*x^2}}}.



{{{100+70*x+70*x+49*x^2}}} Now collect every term to make a single expression.



{{{100+140*x+49*x^2}}} Now combine like terms.



So {{{(10+7x)^2}}} FOILS to {{{100+140*x+49*x^2}}}.



In other words, {{{(10+7x)^2=100+140*x+49*x^2}}}.