Answer:
Douglas can race the go-karts at least 3 times.
Step-by-step explanation:
Given that:
Worth of game card = $20
Cost of go-kart = $3.50 each time
Amount Douglas wants to left = $7.75
Let,
x be the times Douglas can ride go-kart.
20 - 3.50x ≤ 7.75
-3.50x ≤ 7.75 - 20
-3.50x ≤ -12.25
3.50x ≤ 12.25
Dividing both sides by 3.50
Hence,
Douglas can race the go-karts at least 3 times.
Answer: β ≠ ±1
Step-by-step explanation: For a system of equations to have an unique solution, its determinant must be different from 0: det |A| ≠ 0. So,
det ≠ 0
Determinant of a 3x3 matrix is calculated by:
det
β ≠ ±1
For the system to have only one solution, β ≠ 1 or β ≠ -1.