yes you are right, density formula is :
density = mass ÷ vol
Answer:

Step-by-step explanation:

x+1· x+2=7
Simplify x+1· x+2: 2x+2x+1· x+2
Add similar elements: x+1· x=2x=2x+2
2x+2=7[ 2x+2=7 ]
Isolate x for 2x+2=7: x=52 2x+2=7
Subtract 2 from both sides
2x+2−2=7−2
Simplify
2x=5
Divide both sides by 2
2x2 =52 Simplify
Answer: B) The result is a prime number
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Explanation:
Replace x with 5. Then use PEMDAS to simplify.
7x+6
7*5+6
35+6
41
The expression 7x+6 is equal to 41 when x = 5.
The value 41 is prime because its factors are only 1 and 41.
$539 - $35 = $504
$504 : 12 = $42
Per month you pay $42.
Answer: y = 7.5
Step-by-step explanation:
Suppose that y varies directly with x
That is, y∝x
Convert y∝x to a full equation by introducing a constant k to the right hand side.
Therefore, y = kx
Given that y = 10 and x = 20
Substitute y and x in the equation above. We have;
10 = k(20)
10 = 20k
20k = 10
k = 10/20
k = 0.5
Since k = 0.5, the equation y = kx becomes y = 0.5x
Now, to find y if x = 15, substitute x in equation y = 0.5x
Therefore, y = 0.5(15)
y = 7.5