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25 votes
25 votes
Solve the equation for all values of x by completing the square. 5x^2-70x=-230

Solve this ASAP please

User Amuthan
by
2.7k points

2 Answers

12 votes
12 votes


\sf x=\pm √(3)+7

solving step wise:


\sf 5x^2-70x=-230

divide the following by 5


\sf x^2-14x=-46

completing square


\sf (x-(14)/(2))^2-((14)/(2))^2 =-46

should look like this


\sf (x-7)^2-49=-46

simplify by changing sides


\sf x-7=\pm √(3)

final answer:


\sf x=\pm √(3)+7

User Jhchabran
by
3.2k points
28 votes
28 votes

Answer:


x=7 + √(3)


x=7 - √(3)

Explanation:

Given equation:


5x^2-70x=-230

Divide both sides by 5:


x^2-14x=-46

Square half of the coefficient of
x:
(-14 / 2)^2=49
and add this to both sides:


x^2-14x+49=-46+49

Factor the left side and simplify the right side:


(x-7)^2=3

Square root both sides:


x-7=\pm√(3)

Add 7 to both sides:


x=7 \pm √(3)

User Nieto
by
3.0k points