The sum of the first n positive integers is given by the formula:
Sum = n(n + 1) / 2.
For n = 10, the sum = 10(10 + 1) / 2 = 10 × 11 / 2 = 55.
Use the distributive property to multiply:
5(2x + 3) = 5 × 2x + 5 × 3 = 10x + 15.
The area of a square is given by the formula: Area = side².
So, side² = 64, which gives side = √64 = 8 cm.
Average speed = total distance / total time.
Here, average speed = 120 miles / 2 hours = 60 miles per hour.
To solve for x:
Subtract 5 from both sides: 3x = 15
Divide both sides by 3: x = 5
