2 years ago

3x + y = 19 , and x + 3y = 1. Find the value of 2x + 2y

1 answer:

6 0

$3x+y=19 \\
x+3y=1 \\ \\
\hbox{add the sides of the equations:} \\
3x+x+y+3y=19+1 \\
4x+4y=20 \\ \\ \hbox{divide both sides by 2:} \\
2x+2y=10$

The answer is d. 10.

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