Question

please check my work (first one to check my work gets a medal)
use substitution to solve the following system of equations
d+e-f
e=f+d+5
f=2e-4

Answer 1

i got what got:
e:-1
f:-6
d:-10

Answer 2

Is that first equation written correctly ? Or is there supposed to be an equal sign in there ?

Answer 3

my bad d+e-f=-5

Answer 4

f = 2e - 4
sub this into the 1st equation
d + e - f = - 5
d + e - (2e - 4) = - 5
d + e - 2e + 4 = - 5
d - e = -9
d = e - 9
now sub e - 9 in for d and 2e - 4 in for f in the 2nd equation
e = f + d + 5
e = (2e - 4) +( e - 9) + 5 (combine like terms)
e = 3e - 13 + 5
-2e = - 8
e = -8/-2
e = 4

now sub 4 in for e in the 3rd equation
f = 2e - 4
f = 2(4) - 4
f = 8 - 4
f = 4

now sub 4 in for e and 4 in for f in the 1st equation
d + e - f = - 5
d + 4 - 4 = - 5
d = - 5

check...
e = f + d + 5
4 = 4 - 5 + 5
4 = 4 (correct)

or
d + e - f = - 5
-5 + 4 - 4 = - 5
-5 = -5 (correct)

or
f = 2e - 4
4 = 2(4) - 4
4 = 8 - 4
4 = 4 (correct)

I got : d = -5, e = 4, and f = 4

Answer 5

since your the only one that replied i'll give you the medal thanks for the answer too

Answer 6

your quite welcome.....do you see how I did it ?

Answer 7

yeah

Answer 8

good, because I am not very good at explaining...lol :)

Answer 9

yeah you are you just gotta believe in yourself :)

Answer 10

sweet words spoken by the " wild " one.....thank you :)

Answer 11

any time

Answer 12

your the one with sweet words