Linear algebra: extend to a basis?

Linear algebra: extend to a basis?
Let A ={(1,1,0,2),(0,1,0,4),(1,0,-1,0),(0,0,2,5)} then A is a basis for r4. Let B = {(1,0,0,-1),(1,1,0,3)}. show that B is linearly independent. Use A to extend B to a basis of r4.