Question

x+y+z=7
x-y+z=5
x-y-z=-3
solve the system. please show me how to work it out

Answer 1

\[x + y + z = 7 \tag{1}\]\[x - y +z = 5 \tag{2}\]\[x-y-z=-3\tag{3}\]The most effective way to solve is elimination. Add \((1)\) and \((2)\).

Answer 2

right :)))

Answer 3

I don't understand

Answer 4

Not sure how to explain... I think you could use the online resources.

Answer 5

x+y+z=7
x-y+z=5
x-y-z=-3

Let's take 2 equations first. Our goal is to eliminate one variable first.

x+y+z=7
x-y+z=5

Make z the subject for the first one.

z = 7 - y -x

Answer 6

Once you have this, substitute this value of "z" in second equation.

x-y+z=5 <-2

x - y + (7-y-x) = 5

Do you agree till here?

Answer 7

ok yea

Answer 8

Simplify the new equation.

x - y + (7-y-x) = 5

x - y + 7 -y -x = 5

-2y + 7 = 5

-2y = 5 - 7

y = -2/ -2

y = 1

Agree?

Answer 9

ok yeah

Answer 10

Now again take 2 equation.
Let's take the last two now.

x+y+z=7
x-y-z=-3

Solve the first one for x.

x = 7 -z - y

Substitute this value in the second one.

x - y - z = -3

(7-z-y) -y-z =-3

Afer simplification we get

-2y -2z = -10

Answer 11

We already knew the value of y. Which was 1.

-2(1) -2z = -10

Answer 12

ok..

Answer 13

Now solve for z to get it's value.

Answer 14

Finally you'll have the value of y and z. Substitute it in any equation to get the value of x.

Answer 15

2,1,4 ?

Answer 16

^

Answer 17

http://fc07.deviantart.net/fs71/f/2011/337/2/3/like_a_boss_by_mrfletch1000-d4i37i2.jpg

Answer 18

thanks so much