Multiply mentally.(-9 + 5x)(9 + 5x)
A. 25x2 + 90x - 81
B. 25x2 - 90x - 81
C. x2 - 81
D. 25x2 - 81
Answer: D
Mathematics
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Transform the equation by rotating the axes through the given angle. Identify the curve.31x2 + 10
xy + 21y2 - 144 = 0, ? = 30°
A. 
+ 
= 1; ellipse
B. 
+ 
= 1; ellipse
C. y'2 = -4
x'; parabola
D. x'2 = -4
y'; parabola
Mathematics
Use inductive reasoning to predict the next number in the sequence.29, 24, 19, 14, 9
A. 2 B. 4 C. 5 D. 0
Mathematics
Solve the equation for the indicated variable. (Leave ± in your answer, when appropriate.)4?r2 = A for r
A. r = 2?
B. r = ± 
C. r = ± 
D. r = ± 
Mathematics
Simplify each side of the equation and then solve. Check your solution.6x - 7x = 15
A. -15 B. -1 C. 0 D. 15
Mathematics