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2 years ago

Solve x^2 - 4 = 77.

Mathematics

1 answer:

Gennadij [26K]2 years ago

5 0

Answer:

X = 9 or x = -9

Step-by-step explanation:

We want to solve the quadratic equation

${x}^{2} - 4 = 77$

We shall use the square root method

Let us add 4 to both sides to get:

${x}^{2} - 4 + 4 = 77 + 4$

${x}^{2} = 81$

We take square to get:

$x = \pm \sqrt{81}$

$x = \pm9$

The solution is x=9 or -9

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d1i1m1o1n [39]

Step-by-step explanation:

$x^{2} - 4x - 7 = 0$

First, let's move the $7$ to the right-hand side so we can determine what constant we'll need on the left-hand side to complete the square:

$x^{2} - 4x = 7$

From here, since the coefficient of the $x$ term is $-4$ , we know the square will be $(x - 2)$ (since $-2$ it's half of $-4$ ).

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