Question

(а+2)(а+6)+(а-3)(а-4), при а=7

Answer 1

(7+2)(7+6)+(7-3)(7-4)=9*13+4*3=117+12=129

Answer 2

Дано: а=7

(а+2)  7+2=9

(а+6)  7+6=13

9•13=117

(а-3)  7-3=4

(а-4)  7-4=3

4•3=12

117+12=129

(7+2)(а+6)+(а-3)(а-4)=129

Answer 3

To find the value of the expression (а+2)(а+6) + (а-3)(а-4) when а is equal to 7, we simply need to substitute the value of а into the expression and perform the calculations.

Let's do that step by step:

Step 1: Substitute а with 7 in (а+2)(а+6): (7 + 2)(7 + 6) = (9)(13) = 117

Step 2: Substitute а with 7 in (а-3)(а-4): (7 - 3)(7 - 4) = (4)(3) = 12

Step 3: Add the results from Step 1 and Step 2 together: 117 + 12 = 129

So, when а is equal to 7, the expression (а+2)(а+6) + (а-3)(а-4) evaluates to 129.