Question 936430
{{{ -2 + abs( x ) + 9 = 10 }}}
{{{ abs( x ) + 7 = 10 }}}
Subtract {{{ 7 }}} from both sides
----------------------------
{{{ abs( x ) = 3 }}}
The absolute value is always positive
because
{{{ abs( x ) = abs( -x ) }}}
So,
{{{ x = 3 }}}
{{{ x = -3 }}}
are both solutions
--------------------
I can demonstrate this by plotting
{{{ y = abs(x) }}}
{{{ graph( 400, 400, -6, 6, -6, 6, abs(x) ) }}}
Note that when {{{ x = 3 }}}, {{{ y = 3 }}}
but also when {{{ x = -3 }}}, {{{ y = 3 }}}