If anyone could help

Which value of m will create a system of parallel lines with no solution? y = mx - 6 8x - 4y = 12

Julie multiplies 6.27 by 7 and claims the product is 438.9 .explain without multiplying how you know juliesanswer is not correct.find the correct answer

The base of a pyramid is a square with 5 lines of 5cm the slant height of each lateral face of the pyramid is 6 cm what is the surface area of the pyramid