Question

−5x+2y=9 y=7x ​x= y=

Answer 1

$- 5x+2y=9 \\ y=7x$

We know that y=7x, so we just need tu put it into the 1st equation

$- 5x + 2 \times 7x = 9 \\ - 5x + 14x = 9 \\ 9x = 9 | \div 9 \\ 9x \div 9 = 9 \div 9 \\ x = 1$

So we found x. Now we can find y

$y = 7 \times 1 \\ y = 7$

Answer:

x=1, y=7; or (1;7)