Question

If 7 is added to two third of the square of positive number,the sum is 31 .find the number

Answer 1

Answer:

$\sqrt{43}$

Step-by-step explanation:

2/3 $x^{2}$ + 7 = 31

2$x^{2}$ + 7 = 31 * 3

2$x^{2}$ + 7 = 93

2$x^{2}$  = 93 - 7

2$x^{2}$ = 86

$x^{2}$ = 43

x= $\sqrt{43}$

Answer 2

ANSWER:

Given:

• 7 is added to two-third of the square of positive number.

• Sum is 31

To Find:

• The number

Assumption:

• Let the number be x

Solution:

We are given that,

⇒ (²/₃ * x²) + 7 = 31

Transposing 7 from LHS to RHS,

⇒ ²/₃ * x² = 31 - 7

⇒ ²/₃ * x² = 24

Transposing ²/₃ from LHS to RHS,

⇒ x² = 24 * ³/₂

⇒ x² = 12 * 3

⇒ x² = 36

⇒ x = ±6

But as ‘x’ is a positive number,

⇒ x = 6

Verification:

→ Square of the number

⇒ 6² = 36

→ ²/₃ of the square of the number

⇒ ²/₃ * 36 = 2 * 12 = 24

→ Add 7 to it.

⇒ 24 + 7 = 31

HENCE VERIFIED!!