Question

solve the following sets of simultaneous equations x+y=4; 2x-5y=1

Answer 1

Answer:

$x=\;3,\;and\\y=1$

Step-by-step explanation:

$x+y=4\\y=4-x\\Now,\\2x-5y=1\\2x-5(4-x)=1\\2x-20+5x=1\\7x=21\\x=3\\And\;from\;equation\;(1)\\y=4-3\\y=1$

Answer 2

Answer:

${ \red{x + y = 4 - - - - - (1)}}$

${ \red{2x - 5 y = 4 - - - - - (2)}}$

${ \pink{multiply \: eq.(1) \: by \: (2)}}$

${ \red{2x + 2y = 8 }} \\ { \red{2x - 5y = 8 }} \\ { \underline{ \red{ - \: \: \: \: + \: \: \: \: \: - }}}$

${ \red{ 7y = 7 }}$

${\huge{\boxed{ \red{ y = 1 }}}}$

${ \red{ x + y = 4 }}$

${ \red{ x + 1= 4}}$

${ \huge{ \boxed{ \red{ x = 3}} }}$

Step-by-step explanation:

Hope this helps you ✌️