Simplify and evaluate the expression [tex]$\left(4a^2 - 6ab + 9b^2\right)(2a + 3b)$[/tex] for [tex]$a = 2$[/tex] and [tex]$b = 1$[/tex].



Answer :

Sure, let's solve the problem step by step.

Given the expression [tex]\((4a^2 - 6ab + 9b^2)(2a + 3b)\)[/tex] with [tex]\(a = 2\)[/tex] and [tex]\(b = 1\)[/tex]:

1. Evaluate the polynomial inside the parentheses [tex]\((4a^2 - 6ab + 9b^2)\)[/tex]:

[tex]\[ 4a^2 - 6ab + 9b^2 \][/tex]

Substituting [tex]\(a = 2\)[/tex] and [tex]\(b = 1\)[/tex]:

[tex]\[ 4(2)^2 - 6(2)(1) + 9(1)^2 \][/tex]

Calculate each term:

[tex]\[ 4(4) - 6(2) + 9(1) \][/tex]

[tex]\[ 16 - 12 + 9 \][/tex]

[tex]\[ 16 - 12 = 4 \][/tex]

[tex]\[ 4 + 9 = 13 \][/tex]

So, [tex]\(4a^2 - 6ab + 9b^2 = 13\)[/tex] when [tex]\(a=2\)[/tex] and [tex]\(b=1\)[/tex].

2. Evaluate the linear term [tex]\((2a + 3b)\)[/tex]:

[tex]\[ 2a + 3b \][/tex]

Substituting [tex]\(a = 2\)[/tex] and [tex]\(b = 1\)[/tex]:

[tex]\[ 2(2) + 3(1) \][/tex]

Calculate each term:

[tex]\[ 4 + 3 \][/tex]

So, [tex]\(2a + 3b = 7\)[/tex] when [tex]\(a=2\)[/tex] and [tex]\(b=1\)[/tex].

3. Multiply the results from Step 1 and Step 2:

We have:

[tex]\[ (4a^2 - 6ab + 9b^2)(2a + 3b) = (13)(7) \][/tex]

Calculate the product:

[tex]\[ 13 \times 7 = 91 \][/tex]

So, the value of the expression [tex]\((4a^2 - 6ab + 9b^2)(2a + 3b)\)[/tex] when [tex]\(a = 2\)[/tex] and [tex]\(b = 1\)[/tex] is [tex]\(91\)[/tex].

In summary:
- [tex]\(4a^2 - 6ab + 9b^2 = 13\)[/tex]
- [tex]\(2a + 3b = 7\)[/tex]
- The final result is [tex]\(91\)[/tex].