Answer :

Sure! Let's break down and solve the expression step by step: [tex]\((x + 10)(3x + 10)\)[/tex].

To express this as a trinomial, we need to use the distributive property (also known as the FOIL method for binomials), which involves multiplying each term in the first binomial by each term in the second binomial.

### Step-by-Step Solution:

1. First terms:
Multiply the first term of each binomial:
[tex]\[ x \cdot 3x = 3x^2 \][/tex]

2. Outer terms:
Multiply the first term of the first binomial by the second term of the second binomial:
[tex]\[ x \cdot 10 = 10x \][/tex]

3. Inner terms:
Multiply the second term of the first binomial by the first term of the second binomial:
[tex]\[ 10 \cdot 3x = 30x \][/tex]

4. Last terms:
Multiply the second term of each binomial:
[tex]\[ 10 \cdot 10 = 100 \][/tex]

Now we combine all these products:

[tex]\[ (x + 10)(3x + 10) = 3x^2 + 10x + 30x + 100 \][/tex]

Next, we need to combine the like terms (the terms involving [tex]\(x\)[/tex]):

[tex]\[ 10x + 30x = 40x \][/tex]

So, putting it all together, the trinomial form of the given expression is:

[tex]\[ 3x^2 + 40x + 100 \][/tex]

Therefore, the expression [tex]\( (x + 10)(3x + 10) \)[/tex] simplified and expressed as a trinomial is:

[tex]\[ \boxed{3x^2 + 40x + 100} \][/tex]