D would be the right answer
3. 9a+9b
4. 3n+21
5. 30+2q
6. ab+8a
Step-by-step explanation:
x+y=-2
x-y=-6
x=-2-y
(-2-y)-y=-6
-2-2y=-6
-2y=-4
y=2
x=-4
Answer:
Go through the explanation you should be able to solve them
Step-by-step explanation:
How do you know a difference of two square;
Let's consider the example below;
x^2 - 9 = ( x+ 3)( x-3); this is a difference of two square because 9 is a perfect square.
Let's consider another example,
2x^2 - 18
If we divide through by 2 we have:
2x^2/2 -18 /2 = x^2 - 9 ; which is a perfect square as shown above
Let's take another example;
x^6 - 64
The above expression is the same as;
(x^3)^2 -( 8)^2= (x^3 + 8) (x^3 -8); this is a difference of 2 square.
Let's take another example
a^5 - y^6 ; a^5 - (y ^3)^2
We cannot simplify a^5 as we did for y^6; hence the expression is not a perfect square
Lastly let's consider
a^4 - b^4 we can simplify it as (a^2)^2 - (b^2)^2 ; which is a perfect square because it evaluates to
(a^2 + b^2) ( a^2 - b^2)
