Question

Factorise the following
20-45 (m+n)^2

Answer 1

20-45(m+n)

=20(m+n)-45(m+n)

=20m+20n-45m-45n

=20m-45m+20n-45n

= -25m-25n

-25m-25n=0

25(-m-n)=0

-25(m+n)=0

m+n=0

m=0 or n=0

Answer 2

Answer The answer is very simple to this mind boggling question:

Step-by-step explanation:

20-45(m+n)^2

Step 1) 5(4-9z^2) //Let m+n=z &taking out 5 as common from both terms.

Step 2) 5((2)^2 - (3z)^2) // Trying to make the form a^2-b^2=(a+b)(a-b).

Step 3) 5(2+3z)(2-3z).

Step 4) 5(2+3(m+n))(2-3(m+n)) // replacing z by m+n again to arrive at the answer.

Answer=5(2+3(m+n))(2-3(m+n))