`a,x^2-7xy+10y^2`
` =x^2-2xy-5xy+10y^2`
` = x.(x-2y) -5y.(x-2y)`
` = (x-5y).(x-2y)`
`b,5x^2+6xy+y^2`
`=5x^2+5xy+xy+y^2`
`=5x(x+y)+y(x+y)`
`=(5x+y)(x+y)`
`c,x^2-4xy+3y^2`
`=x^2-xy-3xy+3y^2`
`=x(x-y)-3y(x-y)`
`=(x-3y)(x-y)`
`d,x^2+3xy+2y^2`
`=x^2+xy+2xy+2y^2`
`=x(x+y)+2y(x+y)`
`=(x+2y)(x+y)`