MATH
Linear equations
A. Open and Closed Sentences
Open sentence is a mathematical
sentence that could not be determined right or wrong because it still contains
a variable or variables.
Example 1 :
- 3x – 4 = 8
- 5x + 5 < 20
Closed sentence or
statement is a mathematical sentence is true or false can be determined.
Example 2:
1. 2
+ 3 = 5
- 1 + 4 > 3
- Jakarta is the capital of the Republic of Indonesia
Equation is
an open sentence using a dash "=“
Example 3 :
1.
1.2x
+ 5 = 10
2.
x² + 4x – 5 = 0
3.
3.X + 2y = 5
4.
B.Introduction of linear equations
Linear equation is an equation that the change has the
highest rank one.
ax + b = 0, a ≠ 0,a,b € R
value of x that
satisfy a linear equation is called linear completion.
Example 4 :
1. 2x + 5 = 11
2. 3x – 4 = 2 + x
Answer:
1. 2x + 5 = 11
= 2x + 5 + (-5) = 11 + (-5)
= 2x =6
=½ x
2x = ½ x 6
x = 3
2. 3x – 4 = 2 + x
= 3x + (-x) – 4 = 2 + x (-x)
= 2x – 4 = 2
= 2x – 4 + 4 = 2 + 4
= 2x = 6
= ½ x 2x = ½ x 6
x = 3
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