Question

(7b-3)*(7b+3)-7b*(7b+3) при b= -2,6

Answer 1

(7b-3)*(7b+3)-7b*(7b+3)=(7b)²-3²-49b²-21b=49b²-9-49b²-21b=-9-21b

при b=-2,6    -9-21*(-2,6)=-9+54,6=45,6

Answer 2

49в*в-9-49в*в-21в=-9-21в=-9+54,6=45,6

Answer 3

To evaluate the expression (7b-3)(7b+3)-7b(7b+3) when b = -2.6, we simply substitute -2.6 for b and perform the calculations step by step:

Step 1: Substitute b = -2.6 into the expression: (7*(-2.6) - 3) * (7*(-2.6) + 3) - 7*(-2.6) * (7*(-2.6) + 3)

Step 2: Perform the calculations: (-18.2) * (-15.2) - (-18.2) * (-15.2)

Step 3: Continue calculating: 276.64 - 276.64

Step 4: Final result: 0

So, when b = -2.6, the expression (7b-3)(7b+3)-7b(7b+3) equals 0.