Question 1034606
Let {{{ a }}} = Jack's age now
Let {{{ b }}} = Lacy's age now
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(1) {{{ a = 4b }}}
(2) {{{ ( a + 8 ) + ( b + 8 ) = 76 }}}
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Substitute (1) into (2)
(2) {{{ ( 4b + 8 ) + ( b + 8 ) = 76 }}}
(2) {{{ 5b + 16 = 76 }}}
(2) {{{ 5b = 60 }}}
(2) {{{ b = 12 }}}
and
(1) {{{ a = 4b }}}
(1) {{{ a = 4*12 }}}
(1) {{{ a = 48 }}}
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Jack is 48 and Lacy is 12 
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check:
(2) {{{ ( a + 8 ) + ( b + 8 ) = 76 }}}
(2) {{{ ( 48 + 8 ) + ( 12 + 8 ) = 76 }}}
(2) {{{ 56 + 20 = 76 }}}
(2) {{{ 76 = 76 }}}
OK