Is this right. If it is thanks

Prove that the value of the expression 7^8–7^7+7^6 is divisible by 43.

Someone answer this asap for the length, in feet, of a rectangular rug is represented by the expression 5x² + 2x. the width, in feet, is represented by the expression 3x². which expression represents the perimeter, in feet, of the rug? a. 8x² + 2x b. 8x² + 4x c. 16x² + 2x d. 16x² + 4x

Is experimental probibilty the same as the observed frequency in math? i need the answer asap!