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Step-5

Title: Solve the equation

Grade: 8-a Lesson: S3-L1

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

Lesson Steps

Step	Type	Explanation	Answer
1	Problem	Solve the equation \$ \|- x + 21\| = 25 \$
2	Formula:	By using formula	\$\| x \| = a \$
3	Hint	By removing mod we get (+) (or) (-)	\$x = a (or) x = - a\$
4	Step	Here 'a' is '25'	\$-x + 21 = 25(or) -x + 21 = - 25\$
5	Step	Adding "- 21" on both sides	\$- x + \cancel21 - \cancel21 = 25 - 21 (or) -x + \cancel21 - \cancel21 = -25 - 21 \$
6	Step	After cancellation	\$-x = 4 (or)- x = - 46 \$
7	Step	Multiplying Negative sign on both sides	\$-(-x) = - 4 (or) -(-x) = - (-46)\$
8	Step	After multiplication	\$ x = -4 (or) x = 46 \$
9		Answer	D

Step

Type

Explanation

Answer

Problem

Solve the equation
\$ |- x + 21| = 25 \$

Formula:

By using formula

\$| x | = a \$

Hint

By removing mod we get (+) (or) (-)

\$x = a (or) x = - a\$

Step

Here 'a' is '25'

\$-x + 21 = 25(or) -x + 21 = - 25\$

Step

Adding "- 21" on both sides

\$- x + \cancel21 - \cancel21 = 25 - 21 (or) -x + \cancel21 - \cancel21 = -25 - 21 \$

Step

After cancellation

\$-x = 4 (or)- x = - 46 \$

Step

Multiplying Negative sign on both sides

\$-(-x) = - 4 (or) -(-x) = - (-46)\$

Step

After multiplication

\$ x = -4 (or) x = 46 \$

Answer