Find out What is 1/6 of 18?
2 answers:
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Answer: x" = 5.69
Step-by-step 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
take the derivitive to find the slope
so at x=1, the slope is f'(1)=6(1)^2-4=6-4=2
y=mx+b
y=2x+b
find b
at x=1, f(1)=2(1)^3-4(1)=2-4=-2=y
-2=2(1)+b
-2=2+b
-4=b
equation is y=2x-4