Question

1f 2x + 3y = 81 and 7x = 5y, then what is the value of 2y-x?

• A. 5
• B. 7
• C. 2
• D. none of these

Answer 1

Answer:

D. none of these

2x + 3y = 81 and 7x = 5y

2x+3y = 81

sub $x=\frac{5}{7}$

$2\times{\frac{5}{7}}+3y=81$

$3y=81-\frac{10}{7}$

$y=27-\frac{10}{21}$

$2y=54-\frac{5}{21}$

$2y-x=54-\frac{5}{21}-\frac{5}{7}$

$=\frac{1114}{21}$