Answer:
-5
Step-by-step explanation:
When you subtract a negative you end up adding it instead
Answer:
y= (C -Ax)/B
x= (C -By)/A
Step-by-step explanation:
Ax+ By = C
solve for y
Subtract AX from each side
Ax+ By - Ax = C-Ax
By = C -Ax
Divide by B
By /B= (C -Ax)/B
y= (C -Ax)/B
solve for x
Subtract By from each side
Ax+ By - By = C-By
Ax = C -By
Divide by A
Ax/A= (C -By)/A
x= (C -By)/A
Why not look up "standard deviation" yourself, to be sure? But yes, the std. dev. is the sqrt of the variance.