Respuesta :

10r² + 3 = 813

10r² = 813 - 3

10r² = 810

r² = 810 ÷ 10

r² = 81

r = √81

r = 9

So, the value of r is 9

Hope it helpful and useful :)

The answer is r^1=-9, r=-9 because you have to solve the equation.