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3 years ago

Solve the following equation algebraically: x^2=20

Mathematics

2 answers:

amid [387]3 years ago

8 0

Answer:

Step-by-step explanation:

x² = 20

x² - 20 = 0

x² - (√20)² =0

by identity : a² - b² = ( a - b )( a + b) in this exercice : a = x and b =√20

( x - √20)(x + √20) = 0

x - √20 = 0 or x + √20 = 0

x = √20 or x = - √20

but : 20 = 4×5

20 = √(4×5) =√4×√5 = 2√5

Zielflug [23.3K]3 years ago

6 0

Answer:

x = ± 2 $\sqrt{5}$

Step-by-step explanation:

Given

x² = 20 ( take the square root of both sides )

x = ± $\sqrt{20}$ = ± $\sqrt{4(5)}$ = ± 2 $\sqrt{5}$

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$\pi\sin\left(\dfrac\pi2(t+k)\right)+1.8\cos\left(\dfrac{7\pi}5(t+k)\right)=\pi\sin\dfrac{\pi t}2+1.8\cos\dfrac{7\pi t}5$

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