Let's say that Robbie's age is represented by r and Sheila's age is represented by s. Since we know that r is greater than s, we can set up a difference equation of r - s = 12. We also know that r + s = 42. Now, we can simply add the two equations and get that 2r = 54, then finally that r = 54. Therefore, Robbie is 54 years old.
Hope this helps!
Volume of Big Pyramid= 324 cubic feet
Volume of small pyramid= 12
Volume of a pyramid is given as V=⅓xBasexheight
For the big pyramid
324=⅓xbasexheight
But 324= 27x12
Then for the big pyramid,
12=1/3x1/27xbasexheight
For the small pyramid
12=1/3xbasex6
Since both base are similar and from the equations derived so far
1/3x1/27xheight=1/3x6
Height=27x3x1/3x6=162feet
A) 296
B)348
C)828
Plz mark brainliest
(2n + 5k)^2 = (2n + 5k)(2n + 5k)
Here we need to use FOIL
First - 2n * 2n = 4n^2
Outside - 2n * 5k = 10nk
Inside - 5k * 2n = 10nk
Last - 5k * 5k = 25k^2
That gives us 4n^2 + 10nk + 10nk + 25k^2, we can combine 10nk + 10nk to give 20nk, and a final equaion of 4n^2 + 20nk + 25k^2
Use the addition and subtraction theorem:
sin (A + B) = sin A + cos B
sin (A - B) = sin A - cos B
From there it's just a matter of simplification.
sin A cos B = 1/2 [ sin (A + B) + sin (A - B) ]
sin A cos B = 1/2 [ sin A cos B + cos A sin B + sin (A - B) ]
sin A cos B = 1/2 [ sin A cos B + cos A sin B + sin A cos B - cos A sin B ]
sin A cos B = 1/2 [ 2 sin A cos B ]
sin A cos B = sin A cos B
