Question

3а(4-5а)+(а-6)в квадрате при а=корень7

Answer 1

Решение на фотографии

Answer 2

To evaluate the expression 3а(4-5а) + (а-6)в² when а = √7, follow these steps:

Step 1: Replace а with √7 in the expression. Step 2: Evaluate the expression for в².

Step 1: Replace а with √7 in the expression: 3√7(4 - 5√7) + (√7 - 6)в²

Step 2: Evaluate в² when а = √7: в² = (√7)² = 7

Now, we have: 3√7(4 - 5√7) + (√7 - 6)(7)

Next, simplify each term:

1. 3√7(4 - 5√7) = 12√7 - 15(√7)² = 12√7 - 15(7) = 12√7 - 105
2. (√7 - 6)(7) = 7√7 - 42

Finally, combine the simplified terms: 3√7(4 - 5√7) + (√7 - 6)в² = (12√7 - 105) + (7√7 - 42)

Combine like terms: = 12√7 + 7√7 - 105 - 42 = 19√7 - 147

So, the result of the expression 3а(4-5а) + (а-6)в² when а = √7 is 19√7 - 147.