Algebra Flashcards
6 cards from real AMC12 practice questions. Tap to flip, then mark Knew It or Still Learning โ missed cards come back until you master them.
Read the first 6 Algebra flashcards as text
If a+b=5 and ab=4, find a^3+b^3.
Answer: 65
a^3+b^3=(a+b)^3-3ab(a+b)=125-60=65.
The polynomial x^3-6x^2+11x-6 has roots r, s, t. Find r+s+t.
Answer: 6
By Vieta's formulas, the sum of roots equals 6.
Solve 3^(2x) - 4*3^x + 3 = 0. What are the solutions?
Answer: x=0 or x=1
Let u=3^x: u^2-4u+3=0 gives u=1 (x=0) or u=3 (x=1).
If x + 1/x = 5, what is x^2 + 1/x^2?
Answer: 23
Squaring x+1/x=5 gives x^2+2+1/x^2=25, so x^2+1/x^2=23.
A function satisfies f(2x)=2f(x) and f(1)=3. Find f(8).
Answer: 24
f(2)=6, f(4)=12, f(8)=24.
For how many integers n is (n-1)/(n+1) also an integer?
Answer: 4
Writing n-1=(n+1)-2, n+1 must divide 2, so n+1 in {-2,-1,1,2} giving 4 integers.