Question

What is the value of the x variable in the solution to the following system of equations?
7x - 2y = 21
4x + y = 57

21

-21

9

-9

Answer 1

help.... :=(

Answer 2

can you help me ?

Answer 3

sure, i will calculate here

Answer 4

its negative right

Answer 5

7x - 2y = 21 --> eq.[1]
4x + y = 57 --> eq.[2]

Answer 6

from eq.[2] we have y = 57 - 4x.
substitute it in eq.[1] we have:
7x -2(57 -4x) = 21
7x -144 +8x =21
15x = 135
x =9

Answer 7

oh thanks i was using another meathod

Answer 8

wc :)