Question

For a = 3, simplify a2 + 5a + 4 and a2 – 5a.​

Answer 1

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Substitute the value of a = 3 in the given equations.

a^2 + 5a + 4

= 32 + 5(3) + 4

= 9 + 15 + 4

= 28

And,

a^2 – 5a

= 32 – 5(3)

= 9 – 15

= -6

Answer 2

Given,

• $a^2 +5a+4$ and $a^2-5a$ are given.
• $a=3$

To find,

• We have to simplify $a^2 +5a+4$ and $a^2-5a$ for $a=3$.

Solution,

For $a=3$, the value of $a^2 +5a+4$ is 28 and $a^2-5a$ is -6.

We can simply find the value of  $a^2 +5a+4$ and $a^2-5a$ by substituting the value of $a=3$.

   $f(a) = a^2 +5a+4$

   $f(3) = (3)^2+5(3) +4$

          $= 9 +15 +4$

          $= 28$

Now,  $f(a) = a^2-5a$

        $f(3) = (3)^2 -5(3)$

                $= 9-15$

               $= -6$

Hence, for $a=3$, the value of $a^2 +5a+4$ is 28 and $a^2-5a$ is -6.