SaiBook.us Algebra

Example

Title: Find the variable value in the equation

Grade: 7-a Lesson: S1-L6

Explanation: The best way to understand algebra is by looking at some examples. Take turns and read each example for easy understanding.

Examples:

1. Find the value of 'x' in \$30 = 3/(x - 10)\$.

Step 1a

Given equation is that, \$30 = 3/(x - 10)\$.

Explanation: Given equation is that, \$30 = 3/(x - 10)\$.

It is a linear equation with one variable in "x".

Step 1b

Rewrite the equation.

Explanation: Rewrite the equation as \$30/1 = 3/(x - 10)\$.

Step 1c

cross multiply in the equations.

Explanation: Perform cross multiplication in the equation, to make it easier to solve.

\$30/1 = 3/(x - 10)\$

⇒ \$30(x - 10) = 3(1)\$

⇒ \$30x - 300) = 3\$

⇒ \$30x = 3 + 300\$

⇒ \$30x = 303\$

Step 1d

Do cancellation.

Explanation: Divide both sides of the equation by 30

\$30x = 303\$

⇒ \$(30x)/30 = 303/30\$

⇒ \$(cancel30^1x)/cancel30^1 = 303/30\$

⇒ \$x/1 = 303/30\$

⇒ \$x = 303/30\$