Subtract 8d from both sides
21 = 12d + 5 - 8d
Simplify 12d + 5 - 8d to 4d + 5
21 = 4d + 5
Subtract 5 from both sides
21 - 5 = 4d
Simplify 21 - 5 to 16
16 = 4d
Divide both side by 4
16/4 = d
Simplify 16/4 to 4
4 = d
Switch sides
d = 4
<u>Check answer</u>
8d + 21 =12d + 5
Let d = 4
8 × 4 + 21 = 12 × 4 + 5
Simplify 8 × 4 to 32
32 + 21 = 12 × 4 + 5
Simplify 12 × 4 to 48
32 + 21 = 48 + 5
Simplify 32 + 21 to 53
53 = 48 + 5
Simplify 48 + 5 to 53
53 = 53
3: -27
4: 81
5: -243
All you need to do is plug in the numbers into the exponent spot.
For A:
You add the probabilities to get the answer to A: = .75, or 3/4
Note that the probability of ALL THREE of them hitting would be 1/3 x 1/4 x 1/5.
For B:
2/3 and 3/4 is the probability of the other two people MISSING (the remainder of 1/3, 1/4)
1.0 = 100% chance to hit the target, so 1.0 x 2/3 x 3/4 = 1/2
Mark's chance of hitting is 1/5, so do 1/2 x 1/5, = 1/10

1) Let's evaluate that expression, given that a=4.9, b=-7, and c=-0.5

Note that we have rewritten it as a fraction so that we can easily operate. Also, we have applied here the PEMDAS order of operations, prioritizing the exponents.
Answer:
The answer is 27 miles and option b will give that.
Step-by-step explanation:
1.75 + 0.45m = 13.90
m = (13.90 - 1.75) / 0.45
m = 27 miles
Hope this helped