the square of a number is 30 more than the number. the number is positive. find the number.?

Question

(quadratic equations)

.

Answer 1

let x be the number

from the given statement...

x^2 = 30 + x
solving this equation... x^2 - x -30 = 0
factoring the left side... (x - 6)(x + 5) = 0
equating each factors to the right side... x - 6 = 0 OR x + 5 = 0
then... x = 6 OR x = -5...

but since you said that the number should be positive..we reject the value of -5 and choose 6 as the value of the number.

Answer 2

OK. So x²=x+30 and
x²-x-30=0
(x-6)(x+5)=0 => x=-5 or x=6 and the problem specifies the positive answer, so..........
x=6
Check 6²=36=6+30

Doug

Answer 3

x^2 = 30 + x
x^2 - x - 30 = 0
x^2 - 6x + 5x - 30 = 0
(x - 6)(x + 5) = 0

x= -5, 6
but x > 0,

so x = 6

Answer 4

1) x^2 = x + 30
2) x^2 - x - 30 = 0
3) (x + 5)(x - 6) = 0
4) x = -5, 6

positive --> x= 6

Answer 5

6 x 6 = 36

36 - 6 = 30

Answer 6

x² = 30 + x
x² - x - 30 = 0
x² - 6x + 5x - 30 = 0
x(x-6)+5(x-6) = 0
(x+5)(x-6) = 0
x = {-5, 6}

The question specifies that x must be positive.
x = 6