English: How social media brought changes in you pl explain the answer of this

How social media brought changes in you pl explain

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20.10.2022

Question:

Fernando evaluated the expression below.

$\frac{5(9-5)}{2} + (-2)(-5) + (-3)^2 = \frac{5(4)}{2} -10 + 9 = \frac{20}{2} - 10 + 9 = 10 - 10 + 9 = 9$

What was Fernando's error?

- Fernando evaluated the numerator of the fraction incorrectly.

- Fernando simplified 20/2 incorrectly.

- Fernando incorrectly found the product of –2 and –5.

- Fernando evaluated (-3)² incorrectly.

- Fernando incorrectly found the product of –2 and –5.

Explanation:

Given

$\frac{5(9-5)}{2} + (-2)(-5) + (-3)^2 = \frac{5(4)}{2} -10 + 9 = \frac{20}{2} - 10 + 9 = 10 - 10 + 9 = 9$

Required

Spot the error

The error in this evaluation is the product of -2 and -5 at step 2

When a negative number (-2) is multiplied by a negative number (-5), the outcome of the multiplication is always a positive number (10).

So, the result of -2 * -5 is 10 but Fernando incorrectly calculated it as -10.

Solving the expression, correctly

$\frac{5(9-5)}{2} + (-2)(-5) + (-3)^2 = \frac{5(4)}{2} + 10 + 9$

$\frac{5(9-5)}{2} + (-2)(-5) + (-3)^2 = \frac{20}{2} + 10 + 9$

$\frac{5(9-5)}{2} + (-2)(-5) + (-3)^2 = 10 + 10 + 9$

$\frac{5(9-5)}{2} + (-2)(-5) + (-3)^2 = 29$

Hence, the actual result of the expression is 29 (not 9 as calculated by Fernando).

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