## Pooh_ 3 years ago Evaluate the following expression for a = 6 and b = -2 3a + b2 + 4b – a A. 4 B. 12 C. 8 D. 16

1. phi

why don't you replace a with 6 and b with -2 and do the arithmetic?

2. Pooh_

*3a + b^2 + 4b – a

3. phi

yes, but you did not put in 6 everywhere there is an "a" and -2 for every b

4. Pooh_

3(6) + (-2)^2 + 4(-2) - 6 is that what you mean?

5. phi

yes. now do the arithmetic

6. phi

you do know that 3(6) is short for 3*6 (3 times 6) right?

7. Pooh_

Omg of course ...I already did what you're talking about. I just never get the same answer as the multiple choice

8. phi

do it in steps what is 3*6 what is (-2)^2 what is 4*-2 -6 now add them up

9. Pooh_

Wait ..why the 4 isn't -4 ?

10. phi

3(6) + (-2)^2 + 4(-2) - 6 write the answers to each multiplication (or square for (-2)^2 ) below each term

11. Pooh_

18 + (-4) + (-8) - 6

12. phi

do you know that (-2)^2 is short hand for -2 * -2 do you think -2 * -2 is -4?

13. Pooh_

Oh no i didn't know it was -2. Lol thanks for explaining

14. phi

btw, if you see (-2)^3 that means -2* -2 * -2 which is (-2*-2) * -2 or 4*-2 or -8

15. Pooh_

Yes, i know that. Thanks

16. phi

did you get a final answer?

17. Pooh_

Yes, 8.