P / 9 = 72
Multiply both sidess by 9
P / 9 (9) = 72 (9)
p = 648
So first, we want to substitute in 15 to all the x variables.
So,
3x - 8y = 5
Becomes
3 * 15 - 8y = 5
Or,
45 - 8y = 5
So here, you can subtract 45 from both sides to move all like terms to one side.
-8y = 5 - 45
And then simplify:
-8y = -40
Then divide both sides by -8
y = 5
First term: a(1) = 4; common ratio: r = 2
Then:
a(n) = 4(2)^(n-1)
Check: Predict the 4th term using this formula:
a(4) = 4(2)^3 = 4(8) = 32 (correct)
-2x+9. just distribute a -1
