Help with Math Questions

I assume it means that  Row 2 is replaced with the old row2 - 0.5 of row1

BUT the terminology is nor correct.

So Row2 would become

-6-2,      -3-1.5,     12-0

row 1 would stay the same as it was to start with.

Jenny (a regular poster)   explained the terminology to me in this way :

R2  - (1/2)R1     means to  take Row 2, subtract (1/2)R1   and put the result in Row 1

(1/2)R1  =  2    3/2     0

So    R2 - (1/2)R1  =    (  -6 - 2 )  (-3 - 3/2)  (12 - 0)  =    -8     -9/2     12

So.....the martix should be

-8    -9/2   12

-6     -3     12

Melody is correct......this terminolgy is NOT correct.....it should be

R2 - (1/2)R1    →   ( where to put the result )