Question 1141834
1) {{{ 8x + 5y = 180.5 }}}
2) {{{ 12x + 6y = 261 }}}
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Divide both sides of 2) by {{{ 3 }}}
2) {{{ 4x + 2y = 87 }}}
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Multiply both sides of 1) by {{{ 2 }}}
Multiply both sides of 2) by {{{ 5 }}}
1) {{{ 16x + 10y = 361 }}}
2) {{{ 20x + 10y = 435 }}}
Subtract 1) from 20
2) {{{ 20x + 10y = 435 }}}
1) {{{ -16x - 10y = -361 }}}
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{{{ 4x = 74 }}}
{{{ x = 18.5 }}}
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Plug this result back into 1) or 2)
2) {{{ 4*18.5 + 2y = 87 }}}
2) {{{ 74 + 2y = 87 }}}
2) {{{ 2y = 13 }}}
2) {{{ y = 6.5 }}}
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check:
1) {{{ 8*18.5 + 5*6.5 = 180.5 }}}
1) {{{ 148 + 32.5 = 180.5 }}}
1) {{{ 180.5 = 180.5 }}}
OK
2) {{{ 12*18.5 + 6*6.5 = 261 }}}
2) {{{ 222 + 39 = 261 }}}
2) {{{ 261 = 261 }}}
OK