Nobody's going to write an essay for you dude
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)
48$ for store a and 45$ for store b so the difference is 3$ in favor of store b
Tim has 56 more postcards than Paul.
Step-by-step explanation:
Total postcards boys have = 280
Let,
x = Paul's postcards
y = Shawn's postcards
z = Tim's postcards
According to given statement;
x + y + z = 280 Eqn 1
Eqn 2
Eqn 3
Putting value of y from Eqn 3 in Eqn 2
Eqn 4
Putting value of x and y from Eqn 4 and Eqn 3 in Eqn 1
Multiplying both sides by 
Putting z=120 in Eqn 3
Putting y=96 in Eqn 2
Difference of Tim and Paul = 120-64 = 56
Tim has 56 more postcards than Paul.
Keywords: linear equation, substitution method
Learn more about substitution method at:
#LearnwithBrainly
Answer:
x = 2, y = -3
Step-by-step explanation:
Add them together and get
9x + 8y - 9x - 9y = -6 + 9
-y = 3
so y = -3.
Sub it into the first equation and get
9x + 8(-3) = -6
9x - 24 = -6
9x = -6 + 24 = 18
x = 18/9 = 2
