Question

30a-5(a+3)2 при а=корень3

Answer 1

30а-(5а-15)2=30а-10а-30=20а-30

Answer 2

To evaluate the expression 30a - 5(a + 3)^2 when a = √3, we substitute √3 for a in the expression and perform the calculations step by step.

Step 1: Replace a with √3 in the expression. 30√3 - 5(√3 + 3)^2

Step 2: Simplify the expression inside the parentheses. 30√3 - 5(√3 + 3)(√3 + 3)

Step 3: Expand the squared term (√3 + 3)^2. 30√3 - 5(√3 + 3)(√3 + 3) = 30√3 - 5(√3 * √3 + √3 * 3 + 3 * √3 + 3 * 3)

Step 4: Simplify the multiplication inside the parentheses. 30√3 - 5(3 + 3√3 + 3√3 + 9)

Step 5: Combine like terms. 30√3 - 5(3 + 6√3 + 9) = 30√3 - 5(12 + 6√3)

Step 6: Distribute the -5 to each term inside the parentheses. 30√3 - 5(12 + 6√3) = 30√3 - 5 * 12 - 5 * 6√3

Step 7: Simplify the multiplication. 30√3 - 5 * 12 - 5 * 6√3 = 30√3 - 60 - 30√3

Step 8: Combine like terms. 30√3 - 60 - 30√3 = (30√3 - 30√3) - 60 = 0 - 60 = -60

Therefore, when a = √3, the expression 30a - 5(a + 3)^2 is equal to -60.