Question

can you tell me what formula in this questions
x-2y=17 , 3x-4y=1

Answer 1

Its simultaneous equations right? so multiply the first equation (1) x2 to get 2x-4y=34.
Call it equation (3).

Then do equation (2) - equation (3) which gives x = - 33

Then sub into equation (1) -33 -2y = 17
2y = 17+33 = 50
y = 25

Answer 2

whooops y = -25 my bad

Answer 3

nevermine ， thank you