If the value of b is 7,then what is the value of the expression -3b^2+25=?

Question

A.172
B.122
C-122
D.17

Answer 1

Just substitute

-3b^2+25 = ?
-3(7^2) + 25 = ?

Following order of operations
-3(49) + 25 = ?
-147 + 25 = ?
? = - 122

So the correct answer would be C

Answer 2

I presume that you are an algebra begginer. Dont be "scared" by such questions... they are quite easy once you understand that instead of b, you just write 7. The most confusing and important thing to remember is the order of doing things: BIMDAS -brackets, indices ie. ^2s, multiplication, division, adding and substraction. Just do all steps using this order


-3b^2+25=?

Just replace b with 7, and first do the BRACKETS & INDICES
-3(7^2) + 25 = ?
-3 (49) + 25 = ?

Remember brackets just mean multiplication: MULTIPLICATION

-3*49 + 25 = ?
- 147 + 25 = ?

And finally ADDING/SUBTRACTION

-122 = ?

So the answer is -122

Answer 3

C:-122

-3(7^2)+25=
-3(49)+25=
-147+25=
-122
Note: order of operations means that you square before multiplying

Answer 4

Alright, the problem is -3(7)^2+25. In order of operations, we know that the correct order to solve a problem is parentheses, exponents, mult/div, add/sub. Now, we don't have any real parantheses in the problem, so exponents are first.

7^2 = 49.
49 x -3 = -147
-147 + 25 = -122. C.

Hope it helps.

Answer 5

122

Answer 6

C. Make sure you do the ^2 before the x(-3)

Answer 7

C. -122

Answer 8

That's cheating. If this is a homework question then you just want an answer. That's cheating.

Answer 9

well, im going to say "c" just because of the fact that it has to be a negative number and that is the only one.

Answer 10

C