Nonlinear Equations and Systems Flashcards
7 cards from real Bluebook SAT Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Nonlinear Equations and Systems flashcards as text
A quadratic equation has roots x = 2 + √3 and x = 2 − √3. What is the quadratic equation?
Answer: x² − 4x + 1 = 0
Sum = 4, product = (2)² − (√3)² = 4 − 3 = 1; equation: x² − 4x + 1 = 0.
The height of a projectile is modeled by h = −5t² + 20t + 60. At what positive time t does the projectile hit the ground (h = 0)?
Answer: t = 6 only
−5t² + 20t + 60 = 0 → t² − 4t − 12 = 0 → (t−6)(t+2) = 0 → t = 6 (positive) or t = −2 (rejected).
If 2x² − 8 = 0, what are the solutions for x?
Answer: x = ±2
2x² = 8 → x² = 4 → x = ±2.
The system y = x² − x − 6 and y = 2 is solved. What is the sum of the x-coordinates of the intersection points?
Answer: 1
x² − x − 6 = 2 → x² − x − 8 = 0; by Vieta's formulas, sum of roots = −(−1)/1 = 1.
What value of c makes x² + 10x + c a perfect square trinomial?
Answer: 25
For a perfect square: c = (b/2)² = (10/2)² = 25.
For the system y = x² − 1 and y = 3x − 3, at which x-values do the graphs intersect?
Answer: x = 1 and x = 2
x² − 1 = 3x − 3 → x² − 3x + 2 = 0 → (x−1)(x−2) = 0 → x = 1 or x = 2.
The quadratic y = −x² + 6x − 5 has a maximum value. What is that maximum value?
Answer: 4
Vertex x = 6/(2·1) = 3; y = −9 + 18 − 5 = 4.