Question 1156900
Note that if {{{ x = 3 }}}, then {{{ x - 3 = 0 }}},
and {{{ x = 3 }}} is a root of the quadratic
{{{ f(x) = ( x - 3 )*( x -(-7) ) }}}
{{{ f(x) = ( x - 3 )*( x + 7 ) }}}
{{{ f(x) = x^2 - 3x + 7x - 21 }}}
{{{ f(x) = x^2 + 4x - 21 }}}
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check:
{{{ x = 3 }}}
{{{ f(3) = 3^2 + 4*3 - 21 }}}
{{{ f(3) = 9 + 12 - 21 }}}
{{{ f(3) = 0 }}}
You can check ( x = -7 )
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{{{ f(x) = ( x - 12 )*( x - 2 ) }}}
Multiply this out and follow the 1st answer