Evaluate each expression if x=6 , y=8 , and z=3. (show your work.)
1. 2 (x + z)-y
2. 5x - (y+2z)
3. x^2 + y^2 - 10z
4. z^3 + (y^2 - 4x)
5. y + xz/ 2
6. 3y + x^2/z

1. 2 (x + z)-y

=2 (6+3)-8

=(2×9)-8

=18-8

=10

2. 5x - (y+2z)

=5×6 - (8 + 2×3)

=30 - (8 +6)

=30 - 14

= 16

3. x^2 + y^2 - 10z

6^2 + 8^2 - 10×3

36 + 64 -30

70

4. z^3 + (y^2 - 4x)

3^3 + 8^2 - 4×6

27 + 64 -24

70

5. y + xz/ 2

8 + (6×3)/3

8 + 18/3

8 + 6

14

6. 3y + x^2/z

24 + 36/3

24 + 12

36

step-by-step explanation: a reaction is first order. if the initial reactant concentration is 0.0200 m, and 25.0 days later the concentration is 6.25 x 10-4 m, then its half-life is:

.bjbjk.b,j.l.

step-by-step explanation: