Plz solve the 7th question immediately ....Help me......

Mathematics

1 answer:

Lynna [10]3 years ago

3 0

Answer:

The value of x is 8cm. The length of 3 sides are 8cm, 15cm and 17cm.

Step-by-step explanation:

Using Pythagoras' Theorem, a²+b² = c² :

Let a be x cm,

Let b be x+7 cm,

Let c be 2x+1 cm

x² + (x+7)² = (2x+1)²

x² + x² + 14x + 49 = 4x² + 4x + 1

2x² + 14x + 49 = 4x² + 4x + 1

Then, move all the variables to one side and solve it to find the value of x :

4x² + 4x + 1 - 2x² - 14x - 49 = 0

2x² - 10x - 48 = 0

2(x² - 5x - 24) = 0

x² - 5x - 24 = 0

(x-8)(x+3) = 0

x - 8 = 0

x = 8 cm

x + 3 = 0

x = -3 cm (rejected)

Substitute the x value into the length of a,b and c :

a = x

= 8 cm

b = x + 7

= 8 + 7

= 15 cm

c = 2x + 1

= 2(8) + 1

= 16 + 1

= 17 cm

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1 Answer

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