Simultaneous Linear Eq.

# 2x2 matrix determinant
def det2x2(m):
  a,b = m[0]
  c,d = m[1]
  return 1 / (a*d - b*c)

# 2x2 matrix inverse
def inv2x2(m):
  det = det2x2(m)
  a,b = m[0]
  c,d = m[1]
  return [[d*det,-b*det],[-c*det,a*det]]

# Vec2 times 2x2 matrix
def vec2Mul(v,m):
  x = v[0]*m[0][0] + v[1]*m[0][1]
  y = v[0]*m[1][0] + v[1]*m[1][1]
  return [x, y]

# Solve
# 4p+q=6
# 2p-q=–3
v = [6, -3]
m = [[4, 1], [2, -1]]
u = vec2Mul(v,inv2x2(m))
print("p = ",u[0])
print("q = ",u[1])