Question 285571
solve {{{ f(x)= 2x^2 + 2x -4 }}}
since this is in the form of {{{ ax^2 + bx + c = 0 }}}, I would simply solve it using the quadratic formula:
{{{ x[1, 2] = (b+-sqrt( b^2-4ac ))/2a }}} <br>

using your data in () it would be:
{{{ x[1, 2] = ((2)+-sqrt( (2)^2-4(2)(-4) ))/2(2) }}} <br>
solving that for {{{ x[1] }}} and {{{ x[2]}}}
will give you your 2 answers and bob's your uncle!