Question

solve using substitution method
4m+n=18
m-7n=19

Answer 1

28+7n=126
m-7n=19

Answer 2

29M=145
M=5

Answer 3

29m=145 m=145/29 m=5

Answer 4

N=-2

Answer 5

n=2

Answer 6

n=-2

Answer 7

those answers are wrong

Answer 8

well just take the second equation and do this....
m-7(4m+n)=19

Answer 9

m-28m+7n=19

Answer 10

-27m+7n=19

Answer 11

4m+n=18
m-7n=19 therefore m=7n +19
substitute into 4m+n=18
4(7n +19) = 18
28n -76 =18
subtract 76 from both sides
28n = -58
divide by 28 both sides
n =29/14

Now feed this value of n into the other equation to find m

Answer 12

Sorry thatshould read -29/14

Answer 13

can you help me do that?

Answer 14

Yes
4m+n=18 but n =-29/14
So
4m - (-29/14) = 18
4m +29/14 = 18
4m = 18 -29/14
4m = 223/14
divide by 4
m =223/56

Now check both values of m and n in the second equation.

Answer 15

First take the first equation and solve for N. now take what you got for N and plug it into the second equation for the N and solve for M. then you should have the two answers.

Answer 16

shouldn't it have been 4(7n+19)+n= 18?

Answer 17

Chris, I understand it enough to know that is part of solving. I really do write down these steps and study them...If I continue getting the wrong answers I put the questions on here.

Answer 18

Gianfranco which one gets listed first the m or n? I know in x and y x always goes first.

Answer 19

M=5 n = -2 sorry rachel it is very early here!

Answer 20

lol it is ok. so M goes first?

Answer 21

wow

Answer 22

go figure

Answer 23

Hav you graphed the lines to see the point of intersection as that will also give you a rtesult?

Answer 24

Should it go (m,n)?

Answer 25

I only have to solve for these specific problems but yes I did do some of those problems

Answer 26

thanks for the medal shad1

Answer 27

id give you one but i dont know how

Answer 28

4m+n=18 m-7n=19
so m=19+7n
so 4(19+7n)+n=18
29n=18-76=-58
so n=-2
so m=5