Answer:
a). 59.049°C
b). 2.1179 seconds
Step-by-step explanation:
Expression representing the final temperature after decrease in temperature of the metal from 100°C to T°C is,
T = 
where x = duration of cooling
a). Temperature when x = 5 seconds
T = 100(0.9)⁵
= 59.049
≈ 59.049°C
b). If the temperature of the metal decreases from 100°C to 80°C
Which means for T = 80°C we have to calculate the duration of cooling 'x' seconds
80 = 
0.8 = 
By taking log on both the sides
log(0.8) =log[
]
-0.09691 = x[log(0.9)]
-0.09691 = -0.045757x
x = 
x = 2.1179
x ≈ 2.1179 seconds
Answer:
it would be 2d - 60
Step-by-step explanation:
Because if you susbtract d from 3d it would be 2d cause d is like a number in this unit
Answer:
-4 and 8
Step-by-step explanation:
trust me
2x + 3y +2(x-y) - 3x
2x + 3y + 2x - 2y - 3x ( get rid of the bracket by multipling 2 by the x -y)
2x + 2x - 3x + 3y - 2y ( group like terms)
x + y (final answer)