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firebucks74 firebucks74
wrote...
Posts: 83
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11 years ago
I need help solving this question. It is solving systems of equations by substitution
4x+5y=11
y=3x-13
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wrote...
11 years ago
sub y=3x-13 into 4x+5y=11

i.e 4x+5(3x-13) =11
4x+15x-65=11
19x=76
x=4

y=3x4-13 = -1
wrote...
11 years ago
4x+5y=11 and you know y=3x-13 so you replace y in the original equation with the second known equation and solve
4x+5(3x-13)=11
4x+15x-65=11
19x-65=11
19x=76
x=4

Hope this helps
wrote...
11 years ago
X = 4
Y = -1
wrote...
11 years ago
4x+5y=11
y=3x-13

substituting equation 2 to equation 1

4x+5(3x-13)=11
4x+15x-65=11
19x-65=11
  19x=11+65
  19x=76
    x=4 answer

plugging x=4 to equation 2

 y=3(4)-13
 y=12-13
 y=-1 answer
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