Question 1059705
{{{ y^2 - 3y = 10 }}}
{{{ y^2 - 3y + ( 3/2 )^2 = 10 + ( 3/2 )^2 }}}
{{{ y^2 - 3y + 9/4 = 40/4 + 9/4 }}}
{{{ y^2 - 3y + 9/4 = 49/4 }}}
{{{ ( y - 3/2 )^2 = (7/2 )^2 }}}
Take the square root of both sides
{{{ y - 3/2 = 7/2 }}}
{{{ y = 10/2 }}}
{{{ y = 5 }}}
and, taking the negative square
root of {{{ (7/2)^2
{{{ y - 3/2 = -7/2 }}}
{{{ y = -4/2 }}}
{{{ y = -2 }}}
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check:
{{{ y^2 - 3y = 10 }}}
{{{ 5^2 - 3*5 = 10 }}}
{{{ 25 - 15 = 10 }}}
{{{ 10 = 10 }}}
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{{{ (-2)^2 - 3*(-2) = 10 }}}
{{{ 4 + 6 = 10 }}}
{{{ 10 = 10 }}}
OK