Question 256939
Here is the original equation
{{{(x+3)*(x-3)= 40}}}
step 1 - foil the left side to get
{{{x^2 - 9 = 40}}}
step 2 - add 9 to get
{{{x^2 = 49}}}
step 3 - take a square root to get
{{{x=7}}}, {{{x=-7}}}
In this case there are no double roots.
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to check let x = 7 and we get
(7+3)(7-3) = 40 - - - > 10*4 = 40 = 40 [true]
Now let x = -7
(-7+3)(-7-3) = 40 - - > (-4)(-10) = 40  = 40 [true]