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lutik1710 [3]
3 years ago
6

Sergey is solving 5x2 + 20% – 7 = 0. Which steps could he use to solve the quadratic equation by completing the

Mathematics
2 answers:
Mrac [35]3 years ago
6 0

Answer:

5(x^2+4x)=7

5(x^2+4x+4)=7+20

(x+2)=\pm\sqrt{\frac{27}{5}}

Step-by-step explanation:

we have

5x^2+20x-7=0

step 1

Group terms that contain the same variable, and move the constant to the opposite side of the equation

5x^2+20x=7

step 2

Factor 5 left side

5(x^2+4x)=7

step 3

Complete the square

5(x^2+4x+2^2)=7+2^2(5)

5(x^2+4x+4)=7+20

5(x^2+4x+4)=27

step 4

Rewrite as perfect squares

5(x+2)^2=27

step 5

(x+2)^2=\frac{27}{5}

(x+2)=\pm\sqrt{\frac{27}{5}}

(x+2)=\pm\frac{3\sqrt{15}}{5}

step 6

x=-2\pm\frac{3\sqrt{15}}{5}

ki77a [65]3 years ago
4 0

Answer:

b, c, and d

Step-by-step explanation:

I took the test

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If a complex number is z=a+ib, then the trigonometric form of complex number is

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