183,558 views
23 votes
23 votes
Solve for x : 2(x^2+9)-4=0

User Janac Meena
by
3.0k points

2 Answers

13 votes
13 votes

Answer:

no solution

Explanation:

multiply 2 and get 2x^2+18-4=0

combine like terms

2x^2+14=0

subtract 14

2x^2=-14

there can't be a square root of a negative number so there's no solution

User Pranav C Balan
by
2.9k points
20 votes
20 votes

Answer:

x = ±i sqrt(7)

Explanation:

2(x^2+9)-4=0

Add 4 to each side

2(x^2+9)-4+4=0+4

2(x^2+9)=4

Divide by 2

2(x^2+9)/2=4/2

(x^2+9)=2

Subtract 9 from each side

x^2 +9-9 = 2-9

x^2 = -7

Taking the square root of each side

sqrt(x^2) =sqrt(-7)

x = sqrt(-1 *7)

x = ±i sqrt(7)

User Steve Tauber
by
2.9k points