Answer:
- See the graph attached
- x₁ ≈ - 2.1
- x₂ ≈ 0.2
Explanation:
To solve log (−5.6x + 1.3) = −1 − x graphycally, you must graph this system of equations on the same coordinate plane:
- Equation 1: y = log (5.6x + 1.3)
- Equatin2: y = - 1 - x
1) To graph the equation 1 you can use these features of logarithmfunctions:
- Domain: positive values ⇒ -5.6x + 1.3 > 0 ⇒ x < 13/56 (≈ 0.23)
- Range: all real numbers (- ∞ , ∞)
- x-intercept:
log ( -5.6x + 1.3) = 0 ⇒ -5.6x + 1.3 = 1 ⇒x = 0.3/5.6 ≈ 0.054
- y-intercept:
x = 0 ⇒ log (0 + 1.3) = log (1.3) ≈ 0.11
- Pick some other values and build a table:
x log (-5.6x + 1.3)
-1 0.8
-2 1.1
-3 1.3
- You can see such graph on the picture attached: it is the red curve.
2) Graphing the equation 2 is easier because it is a line: y = - 1 - x
- slope, m = - 1 (the coeficient of x)
- y - intercept, b = - 1 (the constant term)
- x - intercept: y = 0 = - 1 - x ⇒ x = - 1
- The graph is the blue line on the picture.
3) The solution or solutions of the equations are the intersection points of the two graphs. So, now the graph method just requires that you read the x coordinates of the intersection points. From the least to the greatest, rounded to the nearest tenth, they are:
- <u><em>x₁ ≈ - 2.1</em></u>
- <u><em>x₂ ≈ 0.2</em></u>
