2x+3y=47 x+3y=40?

X = 40 - 3y

2(40 - 3y) + 3y = 47

80 - 3y = 47

33 = 3y

y = 11

x + 3(11) = 40
x+33 = 40


X = 7 and Y = 11

shouldn't you be doing your homework on your own?!?!

2x + 3y = 47
- 2x - 6y = - 80------ADD

- 3y = - 33
y = 11

x + 33 = 40
x = 7

x = 7 , y = 11

2x + 3y = 47 (solve by using substitution)
x + 3y = 40

x + 3y = 40
x = 40 - 3y

2x + 3y = 47
2(40 - 3y) + 3y = 47
80 - 6y + 3y = 47
-6y + 3y = 47 - 80
-3y = -33
y = -33/-3
y = 11

x + 3y = 40
x + 3(11) = 40
x + 33 = 40
x = 40 - 33
x = 7

∴ x = 7 , y = 11

This is a simultaneous equation so we write it like this:

2x+3y=47
x+3y=40

The two 3ys cancel owt so we can take the two equations away from each other giving:

x+0=7

so x=7

Substitue x into the formula to get y:

(2*7)+3y = 47

so y equals (47-14)/3

y=11

If you put these two values into the equations you will find that they are both correct.

Hope you understand what ive done there

2x+3y=47
x+3y=40

x = 40 - 3y

2(40 - 3y) + 3y = 47
40 - 6y + 3y = 47
-3y = 47 - 40
-3y = -7
y =2.3

x+3y=40
x + 3(2.3) = 40
x + 6.9 = 40
x = 40 -6.9
x = 33.1

2x+3y=47 Eq. (1)
x +3y=40 Eq (2)
-----Subtract---
x = 7

2x+6y=80 Eq. (2) x 2
2x+3y=47 Eq. (1)
-----Subtract---
3y = 33
y = 33/3
y = 11

You need to set up a linear system

2x+3y = 47
x + 3y = 40

solve for x on the second equation... x = 40 - 3y
and substitute it into the first equation and solve for a numeric
value of x...then simply plug in the x value into either equation to
solve for y! You could also solve using linear combinations