Question

find the numerical value of the following expressions.
(a) (2x-3)^2+5 when x =-2. class 7th,subject maths​

Answer 1

Answer:

the answer is 1

Step-by-step explanation:

when x=2 the equation is ((2*2)-3)^7

(4-3)^7=1^7

=1(1^x=1)

Answer 2

Given

• (2x - 3)² + 5
• x = -2

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To Find

The numerical value of the expression.

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Solution

Method 1

Simplify the equation and then put the value of 'x' and find the value of the expression.

Let's simplify the equation step-by-step

⇒ (2x - 3)² + 5

Apply this identity ⇒ (a - b)² = a² - 2ab + b²

⇒ (2x)² - 2(2x)(-3) + (3)² + 5

⇒ 4x² - 12x + 9 + 5

⇒ 4x² - 12x + 14

Now, let's put the value of 'x' in the simplified expression.

⇒ 4x² - 12x + 14

⇒ 4(-2)² - 12(-2) + 14

⇒ 4 × 4 + 24 + 14

⇒ 16 + 24 + 14

⇒ 54

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Method 2

Put the value of 'x' and simplify the expression.

Let's simplify the equation step-by-step

⇒ (2x - 3)² + 5

⇒ (2(-2) - 3)² + 5

⇒ (-4 - 3)² + 5

⇒ (-7)² + 5

⇒ 49 + 5

⇒ 54

∴ The numerical value of the expression ⇒ (2x - 3)² + 5 when x = -2 is 54.

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