Step-by-step explanation:
9x²+bx+ 100
(3x)²+ bx + 10²
(3x)² + 10² + bx
(3x)² + 10² + bx
Answer is C. multiply by 3 - square root 5
using a^2 - b^2 = (a + b)(a - b)
Answer:
6 seconds
Step-by-step explanation:
1/12 mile * 5280 feet/mile = 440 feet per train
50 miles/hour * 1/3600 hr/sec * 5280 ft/mile = 73 1/3 ft/second
one train has to travel 440 feet to pass the other train
440 feet * 1/(73 1/3) sec/ft = 6 seconds
