Dr/dt= 8cmM-¹
dA/dt = ?
but A= πr²
so dA/dr =2πr
but recall
dA/dt = dA/dr • dr/dt
dA/dt = 2πr • 8cmM-¹
dA/dt = 2×π×39 ×8 = 624cm²M-1
Start with

Add 2x to both sides:

Subtract 21 from both sides:

Divide both sides by 5. Since it is positive, we don't have to change the inequality sign:

So, the answer is 
Answer:
b) 25/100 x 79
= 19.75
= 79 - 19.75
= $59.25 (before tax)
7/100 x 59.25
= 414.75/100
= 4.15
= 59.25 + 4.15
= $63.4 (after adding tax)
First we have to take out the percentage of discount and minus it from the total cost . To find the discounted price with tax, we have to take out the percentage of the tax from the discounted amount and add it to the discounted amount to get the total cost.
Step-by-step explanation:
Answer:
No solution
Step-by-step explanation:
x - 4y = 1 --> (1)
5x - 20y = 4 --> (2)
y = (¼)x - ¼ --> (1)
y = (¼)x - ⅕ --> (2)
Since these are 2 parallel lines with different y-intercepts, they will never meet