Caprice adds equations A and B to solve this system of equations. What makes this approach a valid method in general for solving a system of equations?
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Answer: Because the y terms cancel
Step-by-step explanation:
Hi, this approach is called the addition method.
By adding both equations we can cancel one term that contains one variable, and calculate the remaining variable.
For example, in this case:
8x + 3y = 27
+
4x-3y = 9
_______
12x = 36
Now, we can solve for x:
x = 36/12
x = 3
Now, simple replace the value of x in any equation to obtain the value of y:
4x-3y = 9
4(3)-3y =9
12-3y =9
12-9 = 3y
3 =3y
3/3 =y
y=1