Answer:
Below.
Step-by-step explanation:
i) (a + b)^2 = a^2 + 2ab + b^2
= (x + y)^2 + 2(x + y)(x - y) + (x - y)^2
= x^2 + 2xy + y^2 + 2(x^2 - y^2) + x^2 - 2xy + y^2
= x^2 + 2x^2 + x^2 + y^2 - 2y^2 + y^2 + 2xy - 2xy
= 4x^2.
ii) (a - b)^2 = a^2 + b^2 - 2ab
= (x + y)^2 + (x - y)^2 - 2 - 2(x^2 - y^2)
= x^2 + 2xy + y^2 + x^2 - 2xy + y^2 - 2x^2 + 2y^2
= x^2 + x^2 - 2x^2 + y^2 + y^2 + 2y^2 + 2xy - 2xy
= 4y^2.
27
First you dvide 864 by 4 to get 216. Next you multiply the 216 by 2 to find that there are 432 cups in 864 servings. Finally you divide by 16 to turn 432 cups into 27 gallons.
I hope this helps!
40.5
there are 4 laps in 200 metres.
(200m÷50m)
2min 42 sec=120 sec+42sec (162sec)
so,
162÷4=40.5
x = 5y/8
y=8x/5
-3x+7y=5x+2y
7y-2y=5y
-3x+5y=5x
5x+3x=8x
5y=8x
= 
