Mister Exam

1+8x<9 inequation

A inequation with variable

The solution

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1 + 8*x < 9
$$8 x + 1 < 9$$
8*x + 1 < 9
Detail solution
Given the inequality:
$$8 x + 1 < 9$$
To solve this inequality, we must first solve the corresponding equation:
$$8 x + 1 = 9$$
Solve:
Given the linear equation:
1+8*x = 9

Move free summands (without x)
from left part to right part, we given:
$$8 x = 8$$
Divide both parts of the equation by 8
x = 8 / (8)

$$x_{1} = 1$$
$$x_{1} = 1$$
This roots
$$x_{1} = 1$$
is the points with change the sign of the inequality expression.
First define with the sign to the leftmost point:
$$x_{0} < x_{1}$$
For example, let's take the point
$$x_{0} = x_{1} - \frac{1}{10}$$
=
$$- \frac{1}{10} + 1$$
=
$$\frac{9}{10}$$
substitute to the expression
$$8 x + 1 < 9$$
$$1 + \frac{8 \cdot 9}{10} < 9$$
41/5 < 9

the solution of our inequality is:
$$x < 1$$
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Solving inequality on a graph
Rapid solution [src]
And(-oo < x, x < 1)
$$-\infty < x \wedge x < 1$$
(-oo < x)∧(x < 1)
Rapid solution 2 [src]
(-oo, 1)
$$x\ in\ \left(-\infty, 1\right)$$
x in Interval.open(-oo, 1)