Question

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

Answer 1

Answer:

Step-by-step explanation:

x+y=4    ---1

2x-5y=1  ----2

from 1

x=4-y

substitute x value in --2

2(4-y)-5y=1

8-2y-5y=1

8-7y=1

-7y=1-8

-7y=-7

as minus gets cancelled

7y=7

thus

y=1

substitutiny value of y in 1st equation

x+y=4

x+1=4

x=3

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 ✌️