Ho to subtract row from a row in a matrix?

I want to subtract first row of a matrix from a second row.

Considering the matrix to be P= [1 4.6 -7.6 2.2 1.4 6.8 18.2 12; 1 5.6 7.4 2.8 11.4 4.8 28.2 -13; 8 9.5 11.7 13.8 12.6 4.7 -8.8 -23]

please answer this by using a single command.

also explain your answer a bit for me to understand.

[Star Strider]

With:

P= [1 4.6 -7.6 2.2 1.4 6.8 18.2 12;  1 5.6 7.4 2.8 11.4 4.8 28.2 -13; 8 9.5 11.7 13.8 12.6 4.7 -8.8 -23];

either

Out = [P(1,:)-P(2,:); P(3,:)]

Out = 2×8

0 -1.0000 -15.0000 -0.6000 -10.0000 2.0000 -10.0000 25.0000 8.0000 9.5000 11.7000 13.8000 12.6000 4.7000 -8.8000 -23.0000

or:

Out = diff(P)

Out = 2×8

0 1.0000 15.0000 0.6000 10.0000 -2.0000 10.0000 -25.0000 7.0000 3.9000 4.3000 11.0000 1.2000 -0.1000 -37.0000 -10.0000

.

Answer 1

[David Hill]

P= [1 4.6 -7.6 2.2 1.4 6.8 18.2 12;  1 5.6 7.4 2.8 11.4 4.8 28.2 -13; 8 9.5 11.7 13.8 12.6 4.7 -8.8 -23];
p=P(2,:)-P(1,:)

p = 1×8

0 1.0000 15.0000 0.6000 10.0000 -2.0000 10.0000 -25.0000