6x-5y = 15

x=y+3

x=

y=

 x = 0  y = –3

Step-by-step explanation:

We can solve this system by substitution.

use the second equation as a value for x.

Then substitute that value  in place of x in the first equation and solve for y.

6x - 5y = 15 becomes

6(y + 3) - 5y = 15  Distribute 6 × parentheses

6y + 18 - 5y = 15 combine like terms

6y -5y + 18 = 15

y + 18 = 15   Subtract 18 from both sides.

y =15 -18

y = –3

Use this value for y in either equation to solve for x

6x - 5(-3) = 15

6x + 15 = 15    Subtract 15 from both sides, divide by 6 (seems silly!)

x = 0

OR in he second equation,

x = -3 + 3  

Again, x = 0

t = 3

step-by-step explanation:

put t = 3 in this expression :

(3²-1)(3²-2)(3² - 3)(3² - 4) = 8×7×6×5 = 56×30 = 1680

step-by-step explanation: