Question 434745
Let {{{a}}} = cost of a used CD
Let {{{b}}} = cost of a used cassette
given:
(1) {{{ a = 2b - 2 }}}
(1) {{{ a - 2b = -2 }}}
(2) {{{ 2a + 6b = 46 }}}
Multiply both sides of (1) by {{{3}}}
and add (1) and (2)
(1) {{{ 3a - 6b = -6 }}}
(2) {{{ 2a + 6b = 46 }}}
{{{ 5a = 40 }}}
{{{ a = 8 }}}
And
(1) {{{ a = 2b - 2 }}}
(1) {{{ 8 = 2b - 2 }}}
(1) {{{ 2b = 10 }}}
{{{b = 5}}}
$8 is the cost of a used CD
$5 is the cost of a used cassette