if x + y = 2 x + z , x - 2 y = 4 z and x + y + z = 21 , what is the value of y / z ?
x + y = 2 x + 2 z y = x + 2 z - - - - - - - - - - 1 x - 2 y = 4 z x - 4 z = 2 y - - - - - - - - - 2 subtracting equation 1 from equation 2 - 6 z = y y / z = - 6 e is the answer
add(negate(divide(divide(21, 2), negate(divide(21, const_10)))), const_1)