Question 183128
I'll get it out of decimal form and then put it
back to decimal form at end
(1) {{{.17x - .35y = 7}}}
(2) {{{5x + 7y = 76}}}
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Multiply both sides of (1) by {{{100}}}
(1) {{{17x - 35y = 700}}}
(2) {{{5x + 7y = 76}}}
Now multiply both sides of (2) by {{{5}}}
(1) {{{17x - 35y = 700}}}
(2) {{{25x + 35y = 380}}}
Now add (2) and (1)
(1) {{{17x - 35y = 700}}}
(2) {{{25x + 35y = 380}}}
{{{42x = 1080}}}
{{{x = 25.714}}}
Substitute this result back ito (2)
(2) {{{5x + 7y = 76}}}
{{{5*25.714 + 7y = 76}}}
{{{7y = 76 - 128.570}}}
{{{7y = -52.570}}}
{{{y = -7.510}}}
Check answers:
(1) {{{.17x - .35y = 7}}}
(2) {{{5x + 7y = 76}}}
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(1) {{{.17*25.714 - .35*(-7.51) = 7}}}
(1) {{{4.371 + 2.629 = 7}}}
(1) {{{6.9995 = 7}}} close enough
(2) {{{5x + 7y = 76}}}
(2) {{{5*25.714 + 7*(-7.51) = 76}}}
(2) {{{128.57 - 52.57 = 76}}}
(2) {{{76 = 76}}}
OK