1. Distributive Property.
<span>4(3a + 7) + 3(2a + 5)
12a + 28 + 6a + 20
2. Combine like terms
12a + 28 + 6a + 20
18a +48
The equivalent expression is 18a + 48. If a = anything then the expressions will still be equivalent.
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Answer: 672 cars will have defective engine mounds
Step-by-step explanation: 25% of 2,688 is 672
A is not commutative with the above expression
your answer is A
Parallel lines have the same slope
Y = -8x + 8
The slope will be -8
Therefore: y = -8x + b
Plug in the point
7 = -8(9) + b
7 = -72 + b, b = 79
Solution: y = -8x + 79
Answer:
- train: 40 kph
- plane: 140 kph
Step-by-step explanation:
Let t represent the speed of the train in km/h. Then 4t-20 is the speed of the plane. Travel times are the same, so we can use the formula ...
time = distance/speed
and equate the travel times.
110/t = 385/(4t-20)
Cross multiplying gives ...
110(4t -20) = 385t
440t -2200 = 385t . . . . . eliminate parentheses
55t -2200 = 0 . . . . . . . . . subtract 385t
t -40 = 0 . . . . . . . . . divide by 55
t = 40 . . . . . . . . . . . add 40; train's speed is 40 kph
4t -20 = 140 . . . . . . find plane's speed; 140 kph
The train's speed is 40 km/h; the plane's speed is 140 km/h.
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<em>Check</em>
Train's travel time = 110 km/(40 km/h) = 2.75 h.
Plane's travel time = 385 km/(140 km/h) = 2.75 h.
