What is Algebra about?

Quick Education

5 + 2 = ?Which one is true?

5 + 2 = 65 + 2 = 75 + 2 = 8

5 + 2 = ?

5 + 2 = 65 + 2 = 75 + 2 = 8

5 + ? = 7Which one is true?

5 + 1 = 75 + 2 = 75 + 3 = 7

5 + ? = 7

5 + 1 = 75 + 2 = 75 + 3 = 7

5 + x = 7Which one is true?

5 + 1 = 75 + 2 = 75 + 3 = 7

5 + x = 7

5 + 1 = 75 + 2 = 75 + 3 = 7

x + 2 = 7Which one is true?

4 + 2 = 75 + 2 = 76 + 2 = 7

x + 2 = 7

4 + 2 = 75 + 2 = 76 + 2 = 7

x + 2 = 7What is x?

x + 2 = 7X = 5

5 + x = 7What is x?

5 + x = 7X = 2

5 + 2 = xWhat is x?

5 + 2 = xX = 7

5 + x = 7This is algebra. Why?

5 + x = 7It’s because of the x.

5 + x = 7What do you think x is called?

Guess…

XX is called the variable

XX is also called the unknown. Why?

5 + 2 = xBecause when you first start working on a problem, you don’t know what x is until you think about it.

This one’s easy, but what about:

48 - x = 45What is x?

48 - x = 45X = 3

48 – x = 45X = 3 Because 48 – 3 = 45

100 + x = 125What is x?

100 + x = 125X = 25

100 + x = 125X = 25 Because 100 + 25 = 125

X – 3 = 45One way to find x is to substitute numbers until you find the one that makes the equation true.

50 – 3 = 45Is this true?

This is an equation

No because50 – 3 = 47It must equal 45

49 – 3 = 45Is this true?

No because49 – 3 = 46It must equal 45

48 – 3 = 45Is this true?

Yes! because

48 – 3 = 45When you try “plugging” in different numbers for x, it’s called substitution.

Reviewx - 3 = 45X 50 X = 48X 49

This () means “not equal”

Reviewx - 3 = 45X 50 X = 48X 49

This () means “is equal”

Forx + 10 = 15Which is true?X X X

Forx + 10 = 15Which is true?X X X

Forx + 10 = 15Which is true?X X X

When you find the right number for x, the problem is solved and the equation is true!

A couple more, and your done!

322 - x = 222Solve for x?

322 – x = 222X = 100

X = 100 Because 322 - 100 = 222

322 – x = 222

100 b = 25Solve for b?

100 b = 25Solve for b?

Sometimes other letters are used besides x, but mostly x is used.

100 b = 25b = 4

b = 4 Because 100 4 = 25

100 b = 25

322 – x = 222X = 100

X = 100 Because 322 - 100 = 222

322 – x = 222

10=𝑥2

Solve for x?

10=𝑥2

X = 20

10=𝑥2

X = 20

Because10=202

Algebra is all about solving for an unknown like x

Al-Khwarzmi - who founded the discipline of al-jabr