SaiBook.us Algebra

Home Course Section

Schedule Admission Social

Lesson Example Discussion Quiz: Class Homework

Step-5

Title: Evaluating Algebric Expressions

Grade: 6-a Lesson: S2-L5

Explanation: Hello Students, time to practice and review the steps for the problem.

Lesson Steps

Step	Type	Explanation	Answer
1	Problem	Evaluate the expression \$4"s"^3 − 2"s"^2 + 5"s" + 1\$ when s = - 1.
2	Step	The given expression is	\$4"s"^3 − 2"s"^2 + 5"s" + 1\$
3	Step	Substitute - 1 in place of s in given expression	\$4(- 1)^3 − 2(- 1)^2 + 5(- 1) + 1\$
4	Step	Simplify the expression	⇒ 4(-1) - 2(1) - 5 + 1 ⇒ - 4 - 2 - 4 ⇒ - 6 - 4 ⇒ -10
5	Step	Therefore, when s = - 1, the value of the expression \$4"s"^3 − 2"s"^2 + 5"s" +1\$ is - 10.
6	Choice.A	This is incorrect as the correct value obtained by substituting - 1 into the given expression is - 10	- 11
7	Choice.B	This choice proposes - 9 as the evaluated value. This is also incorrect as the correct value obtained by substituting - 1 into the given expression is - 10	- 9
8	Choice.C	This choice correctly suggests - 10 as the evaluated value, which matches the actual result obtained by substituting - 1 into the given expression	- 10
9	Choice.D	This option suggests - 12 as the evaluated value. Yet, upon substituting - 1 into the expression, we find the correct result to be - 10, not - 12. Hence, option D is incorrect	- 12
10	Answer	Option	C
11	Sumup	Can you summarize what you’ve understood in the above steps?

Step

Type

Explanation

Answer

Problem

Evaluate the expression
\$4"s"^3 − 2"s"^2 + 5"s" + 1\$ when s = - 1.

Step

The given expression is

\$4"s"^3 − 2"s"^2 + 5"s" + 1\$

Step

Substitute - 1 in place of s in given expression

\$4(- 1)^3 − 2(- 1)^2 + 5(- 1) + 1\$

Step

Simplify the expression

⇒ 4(-1) - 2(1) - 5 + 1

⇒ - 4 - 2 - 4

⇒ - 6 - 4

⇒ -10

Step

Therefore, when s = - 1, the value of the expression \$4"s"^3 − 2"s"^2 + 5"s" +1\$ is - 10.

Choice.A

This is incorrect as the correct value obtained by substituting - 1 into the given expression is - 10

- 11

Choice.B

This choice proposes - 9 as the evaluated value. This is also incorrect as the correct value obtained by substituting - 1 into the given expression is - 10

- 9

Choice.C

This choice correctly suggests - 10 as the evaluated value, which matches the actual result obtained by substituting - 1 into the given expression

- 10

Choice.D

This option suggests - 12 as the evaluated value. Yet, upon substituting - 1 into the expression, we find the correct result to be - 10, not - 12. Hence, option D is incorrect

- 12

Answer

Option

Sumup

Can you summarize what you’ve understood in the above steps?