1. When there are two events that need to happen, we must multiply the probability of each event happening.
Shawn losing to Mike: 5/8 chance
Shawn losing to Tim: 2/7 chance
5/8 × 2/7 = 10/56 = 5/28
There's a 5/28 chance of Shawn losing to Mike and Tim.
I don't know #2, sorry :/
Hope this helps!
Let's take a look at a perfect square trinomial.

We can distribute this expression to get

.
An important relation to recognize here is that the constant is the square of half of the x value.
Now, if we wanted to add a number to

to make a perfect square trinomial, we could have the value of x and then square it.
Half of 16 is 8, and 8 squared is
The area of the rectangular part = 14 x 20 = 280 sq. cm
The area of the half circle = 1/2 (3.14 x 7^2) = 76.9 sq. cm.
Total area = 280 + 76.93 = 356.9 cm^2
If you're asking about the largest number that can be written with 3 digits in the given base:
• In base 2, the largest number with 3 digits is
111₂ = 1•2² + 1•2¹ + 1•2⁰ = 7
• In base 12, the largest number with 3 digits is
bbb₁₂ = 11•12² + 11•12¹ + 11•12⁰ = 1727
(in base 12, a₁₂ = 10 and b₁₂ = 11)