Question

If 4m-7n=10 and 2m+2n =4 what is the value of 2m-9n?

Answer 1

they want you to find the common solution tothe first 2 equations and use those numbers in the last one

Answer 2

or simply subtract second from first

Answer 3

id multiply 2nd by -2 then add them together

Answer 4

I dont really understand how to do that though... I've tried a lot of numbers for finding the solution to the first one, but it never worked out for the second one, or vice versa

Answer 5

trial and error is a shot in the dark; you have to use numerical methods such as substitution or elimination

Answer 6

subtract second equation from first equation

Answer 7

4m-7n=10
2m+2n =4 <-- multiply this one by -2


4m-7n=10
-4m-4n =-8 ; now add them together
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0 -11n = 2 , now solve for n

Answer 8

oh... thank you

Answer 9

once you know "n"; solving for m is easy :)