Question

Substitute x + y = 10 and x – y = 4

Answer 1

Answer:

x+y=10             -1

x-y=4               -2

x=7

y=3

Step-by-step explanation:

add equation 1 and 2

x+y+x-y = 10+4

2x=14

x=7

Then substitute the value of x into any of the equations.

7-y=4

y=3

By substitution:

From one equation, x+y=10

so x=10-y

Substitute this equation into the other one.

(10-y)-y=4

10–2y=4

2y=6

y=3

Then substitute the value of y into the equation made.

x=10–3=7

therefore x=7 and y=3

Answer 2

Step-by-step explanation:

$x + y = 10 \\ x - y = 4 \\ - - - - - - - \\ 2x = 14 \\ x = \frac{ \cancel{ 14} _{ \: \: 7}}{ \cancel 2 _{ \: \: 1} } \\ x = \underline{ \underline{ 7}} \\ \\ x + y = 10 \\ 7 + y = 10 \\ y = 10 - 7 \\ y = \underline{ \underline{3}}$