Question

Expand and simplify: (x + 5y) (x − 3y)

Answer 1

x^2 - 3yx + 5yx - 15y^2

Answer 2

`(x+5y)(x-3y)=x^2+2xy-15y^2`

Explanation:

We have the expression (x+5y)(x-3y), we have to apply distributive property.

Observation: (a+b)(c+d)=ac+ad+bc+bd

Then,

`(x+5y)(x-3y)=x.x+x.(-3y)+5y.x+5y.(-3y)\\\\=x^2-3xy+5xy-15y^2\\\\=x^2+2xy-15y^2`

`(x+5y)(x-3y)=x^2+2xy-15y^2`