Factorise 49x²-y² class 8​

Can someone 50 first drop menu 0.80 or 0.75 or 1.20 or 4.00 second drop menu 4.00 or 0.75 or 0.25 or 3.75 3rd 15,6,10, or 9 4th yes or no

Ametalworker has a metal alloy that is 30? % copper and another alloy that is 55? % copper. how many kilograms of each alloy should the metalworker combine to create 90 kg of a 50? % copper? alloy?

Which of the binomials below is a factor of this exression? 16x^2+40xy+25y^2 a.4x-5y b. 2x-5y c.4x+5y d.2x+5y