Question

Hello!! I need help with square root please help me!!!

Answer 1

This is actually a cube root, since you need a cube root to cancel out the cube.

C, y = 5

Explanation:

125 = 5 × 5 × 5 = 5^3

5 × 5 × 5 = 25 × 5 = 125.

Therefore the cube root of 125 = 5.

It REALLY helps when you break these into factors.

`\sqrt[3]{125} = 5 , \: as \: {5}^(3) \: = 125`

This is essentially asking what multiplied by itself three times is equal to 125.

Process of elimination can be used for any number cubed that is ≠ 125

i.e : 11.2^3 ≠ 125

11.2^3 = 11.2 × 11.2 × 11.2 = (11.2-1.2)(11.2+1.2)(11.2) = (11.2)((10)(12.4) + 1.2^2) = 124 + 1.44 = (125.44)(11.2) = 125.44(10+1+(2/10)) = 1254.4 + 125.44 + 25.088 = 1404.928 ≠ 125, y ≠ 11.2

I.e : 25^3 = 25 × 25 × 25 = 625 × 25 = (600+25)(25) = 625 + 6(25)(100) = 15000 + 625 = 15625 ≠ 125, y ≠ 25.

And i.e: 15^3 = 15 × 15 × 15 = 225 × 15 = (225)(10+5) = 225(10) + 225(10/2) = 2250 + 2250/2 = 2250 + 1125 = 3375 ≠ 125, y ≠ 15.

Answer 2

Ok so what you need to do is you need to get all the numbers and see which one is the right number so...

A. y = 11.2 that is wrong

B. y = 25 is wrong

C. y = 5 is right

D. y = 15 is wrong.

C is right because it would be 5 times 5 times 5. SO 5 times 5 is 25, and then u times it by 5 and you get 125!

C is correct

Hope this helps!!