How do you solve 81x^2-10=-1?

2 Answers
Jun 2, 2018

x=+-1/3

Explanation:

"isolate "81x^2" by adding 10 to both sides"

81x^2=-1+10=9

"divide both sides by 81"

x^2=9/81=1/9

color(blue)"take the square root of both sides"

sqrt(x^2)=+-sqrt(1/9)larrcolor(blue)"note plus or minus"

x=+-1/3

Jun 2, 2018

x=pm1/3

Explanation:

81x^2=9

x^2=9/81

x=pmsqrt9/81

rArr pm3/9

rArr pm1/3