Answer:

Step-by-step explanation:
Multiply numerator and denominator by √2

Height = 12 cm
Base/width —> half of height —> 12/2 = 6 cm
Area = length x width
Area —> 12x6 = 72
The sticker covers 72 cm of the notebook.
First lets distribute the 5x
5x^2 + 30x = -50
Lets divide every term by 5
x^2 + 6x = -10
To complete the square we have to half the b value, which in this case is 6. Then square it.
Half of 6 is 3, 3 squared is 9
Add that to both sides of the equation
x^2 + 6x + 9 = -1
Find the binomial squared
(x+3)^2 (If you're wondering how i got that please comment)
(x+3)^2 = -1
Take the square root of the equation of both sides
(x+3) = +/- i
x = -3 +/- i
x = -3 - i
and
x = -3 + i
it cant be a negative number or zero
so now you are left with 0.5, 2 and 7.9
15.7 - 0.5 = 15.2 ( 15.2/2 = 7.6) this is possible
15.7 - 2 = 13.7 ( 13.7/2 = 6.85) this is possible
15.7 - 7.9 = 7.8 ( 7.8/2 = 3.9) (7.9/2 = 3.95) since the sides would be shorter than half the base this is not possible to form a triangle
so b can be either 0.5 or 2
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