The goal to proving identities is to transform one side into the other. We can only pick one side to transform while the other side stays the same the entire time. The general rule of thumb is to transform the more complicated side (though there may be exceptions to this guideline).
So I'll take the left hand side and try to turn it into 
One way we can do that is through the following steps:

Since we've shown that the left hand side transforms into the right hand side, this verifies the equation is an identity.
Answer:
34 feet
Step-by-step explanation:
From the question, we are told that:
If the room is 30 feet high at the center and 90 feet wide at the floor,
Entire width of the room = 90 feet = 2a
a = 90/2 = 45
Height of the room = b = 30 feet
Foci (c)² = a² - b²
c = √a² - b²
c = √45² - 30²
c = √1125
c = 33.541019662 feet
Approximately to the nearest whole number = 34 feet
Denise and Donna should each stand 34 ft from the outer wall so that they will be positioned at the foci of the ellipse
Answer:
Step-by-step explanation:
1. (a-b-c) (a2+b2+c2-ab-ac-bc). = (a3-b3-c3).
NOTE : this is an identity 11th identity
2. (98)3
That is 98×98×98= 941192
For example. (1)3
That is 1×1×1= 1
Or (2)3
That is 2×2×2= 8. [ 2×2=4. ]. {4× 2 = 8 )
Thank you
First you want to find the surface area of one box
SA=2(l*w)+2(h*l)+2(h*w)
SA=2(12*12)+2(15*12)+2(15*12)
SA=2(144)+2(180)+2(180)
SA=288+360+360
SA=1008 cm² is for one box
Multiply by 4 to get for 4 boxes
4*1008=4032 cm²