Answer:
36x² - 9y²
Step-by-step explanation:
We see that the given expression (6x + 3y)(6x - 3y) looks just like the expression (a + b)(a - b). When multiplied out, this is a difference of squares identity that I highly recommend you memorise:
(a + b)(a - b) = a² - b²
Here, a = 6x and b = 3y, so plug these in:
(6x + 3y)(6x - 3y) = (6x)² - (3y)² = 36x² - 9y²
Answer:
40
Step-by-step explanation:
2% of 400 is 8
400 x 0.02 = 8
10% of 400 is 40
Answer:
A. (-7 -2)
Step-by-step explanation:
You can eliminate y by multiplying the first equation by 7 and subtracting 6 times the second equation:
7(-3x +6y) -6(5x +7y) = 7(9) -6(-49)
-21x +42y -30x -42y = 63 +294 . . . . eliminate parentheses
-51x = 357 . . . . . . . . collect terms
x = -7 . . . . . . . divide by -51. This matches answer choice A.
Sin (tan^(-1)X)
Sin (1/tan X)
Sin (1/1 / tan X/1)
Tan X = sin X/cos X
Sin (1/1 / sin X/cos X)
Sin (1/1 • cos X/Sin X)
Sin (cos X/sin X )
Cos X.
I believe the correct answer is cos X.