Answer: ab =6
have:
=> a + b + 1 = ab
⇔ a + b + 1 - ab = 0
⇔ b - 1 - a(b - 1) + 2 = 0
⇔ (b - 1)(1 - a) = -2
because a and b are postive integers => (b - 1) and (1 - a) also are integers
=> (b - 1) ∈ {-1; 1; 2; -2;}
(1 -a) ∈ {-1; 1; 2; -2;}
because (b -1).(1-a) = -2 => we have the table:
b - 1 -1 1 2 -2
1 - a 2 -2 -1 1
a -1 3 2 0
b 0 2 3 -1
a.b 0 6 6 0
because a and b are postive integers
=> (a;b) = (3;2) or (a;b) = (2;3)
=> ab = 6
Step-by-step explanation:
Answer:
First know the formula for the area of a circle;
<h2>A = πWhere 'π' represents pi(3.14 or 22/7), and 'r' stands for the radius being squared.
For the first problem, we can see that 12 is our <u>diameter</u>.
And to find the radius, we need to find 1/2 of the diameter (half of the diameter), so;
D/2 = R
Replace with actual values;
12/2 = 6, <u>6</u> is our <u>radius</u>.
Now we plug this into our formula:
A = π
A = 3.14(6^2)
A = 3.14(36)
A = <u>113.04 centimetres</u> is the area of the circle.
For the second problem, we can see that 18 is our <u>diameter</u>.
And to convert the diameter into the radius, we do what we did to the past problem, find 1/2 of the diameter.
So;
D/2 = R
18/2 = 9, <u>9</u> is our <u>radius</u>.
Now we plug this into our formula:
A = π
A = 3.14(9^2)
A = 3.14(81)
A = <u>254.34 inches</u> is the area for this circle.
For the third problem, we can see that our radius is already given, 5.
So now we just simply and easily plug this into our formula;
A = π
A = 3.14(5^2)
A = 3.14(25)
A = <u>78.5 meters</u> is the area for this circle.
