Question

Find the approximate solution(s) to each of the following equations graphically. Use technology to support your

work. Verify the solution sets using the original equations.
a. 2x − 4 = √x + 5

Answer 1

Answer: x" = 5.69

Explanation:

The graphic solution is attached.

Verifying the solution:

Existence condition: x > 0

2x - 4 = √x + 5

√x =2x - 4 - 5

√x =2x - 9 (²)

x = (2x - 9)²

x = 4x² - 36x + 81

4x² - 36x - x + 81 = 0

4x² - 37x + 81 = 0

Δ = -37² - 4.4.81 = 1369 - 1296 = 73

x = 37 ±√73/8

x' = 3.55

x" = 5.69

checking:

2*3.55 - 4 = 3.1

√3.55 + 5 = 6.88 Its not the same ∴ 3.55 is not a solution

2*5.69 - 4 = 7.39

√5.69 + 5 = 7.39 ∴ it's the only solution