Hello.
First of all, let the number be t.
8 times t can be written like this:

Notice that the number is before the variable and the times sign (×) is not there.
We can write it as 8×t, but we usually write it as 8t.
The sum of means we add:
8t+21
Now, "less than" is "<" :

Therefore, the answer is

I hope it helps.
Have a nice day.

Answer:
s= -1
Step-by-step explanation:
7= -10s-3
+3 +3
10=-10s
s= -1
Answer:
Angelina should buy 9 packs of pens and 8 packs of pencils.
Step-by-step explanation:
Each pack of pens = 8 pens
Each pack of pencils = 9 pencils.
Also we know that, Commutative Property of Multiplication states that
a x b = b x a for any two numbers a and b.
So, 8 x 9 = 72 = 9 x 8
Hence, she should buy 9 packs of pens, so she will have 9 x 8 = 72 pens.
And she should buy 8 packs of pencils, she will have 8 x 9 = 72 pencils.