Choose the correct product of (8x − 4)(8x + 4)

64x^2 -16

Step-by-step explanation:

(8x − 4)(8x + 4)

This is of the form

(a-b) (a+b) = a^2 -b^2  Difference of squares

where a =8x and b=4

(8x)^2 - 4^2

64x^2 -16

ok

step-by-step explanation:

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18