Question

I think of a number, if I subtract 10 from my number, then square the result, I get the same answer as if I square my number, then subtract 10 from the result

Answer 1

Answer:

x =5.5

Step-by-step explanation:

The directions say to use x for the number.

"take 10 away from"

x - 10

"then square the result"

(x - 10)^2

"I get the same answer" means the two expressions will be equal to each other.

"if I square my number"

x^2

"then subtract 10 from the result"

x^2 - 10

SET EQUAL TO EACH OTHER.

(x - 10)^2 = x^2 -10

Multiply on the left side.

x^2-20x+100 =x^2-10

subtract x^2 from both sides.

-20x + 100 = -10

subtract 100.

-20x = -110

divide by -20

x = 11/2 or 5.5

CHECK:

(5.5-10)^2=20.25

5.5^2 - 10=20.25

Answer 2

Let the number be x
(x-10) whole square - 10 = x
X^2 +100 -2(x)(10) -10 =x
x^2 - 21x+ 90 =0

Simplyfying, I get this as shown in the image