[tex] - 5x+2y=9 \\
y=7x[/tex]
We know that y=7x, so we just need tu put it into the 1st equation
[tex] - 5x + 2 \times 7x = 9 \\ - 5x + 14x = 9 \\ 9x = 9 | \div 9 \\ 9x \div 9 = 9 \div 9 \\ x = 1[/tex]
So we found x. Now we can find y
[tex]y = 7 \times 1 \\ y = 7[/tex]
Answer:
x=1, y=7; or (1;7)
