Can someone help me? Plzzzzz :c I need it for tmw

Mathematics

2 answers:

lys-0071 [83]3 years ago

5 0

$x-cost\ of\ DVD\\y-cost\ of\ video\ game\\\\ \left \{ {{3x+14y=203\ \ \ } \atop {11x+11y=220\ \ } \right. \\\\ From\ first\ second:\\11x=220-11y\ \ \ \ |:11\\x=20-y\\\\Substitute\ to\ first:\\3(20-y)+14y=203\\60-3y+14y=203\\-3y+14y=203-60\\11y=143\ \ \ \ |:11\\y=13\\\\x=20-13=7\\\\ \left \{ {{y=13} \atop {x=7}} \right.$

Sati [7]3 years ago

3 0

3D+14G=203(11) use elimination 33D+154G=2233
11D+11G=220(-14) to cancel G -154D-154G=-3080

-121D=-847 divide by -121 on both sides
D=7 plug back into equation
11(7)+11G=220
77+11G=220 subtract 77 from both sides
11G=143 divide by 11 on both sides
G=13

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