Answer :
To solve the expression [tex]\(-3b^2 + 25\)[/tex] when [tex]\(b = 7\)[/tex], follow these steps:
1. Substitute the value of [tex]\(b\)[/tex]:
Replace [tex]\(b\)[/tex] in the expression with 7. The expression becomes:
[tex]\[
-3(7)^2 + 25
\][/tex]
2. Calculate the square of 7:
[tex]\(7^2\)[/tex] equals 49. So, the expression updates to:
[tex]\[
-3 \times 49 + 25
\][/tex]
3. Multiply by -3:
Next, multiply 49 by -3:
[tex]\[
-3 \times 49 = -147
\][/tex]
The expression now is:
[tex]\[
-147 + 25
\][/tex]
4. Add 25 to -147:
Finally, add 25 to -147:
[tex]\[
-147 + 25 = -122
\][/tex]
So, the value of the expression [tex]\(-3b^2 + 25\)[/tex] when [tex]\(b = 7\)[/tex] is [tex]\(-122\)[/tex].
Therefore, the correct answer is:
B. -122
1. Substitute the value of [tex]\(b\)[/tex]:
Replace [tex]\(b\)[/tex] in the expression with 7. The expression becomes:
[tex]\[
-3(7)^2 + 25
\][/tex]
2. Calculate the square of 7:
[tex]\(7^2\)[/tex] equals 49. So, the expression updates to:
[tex]\[
-3 \times 49 + 25
\][/tex]
3. Multiply by -3:
Next, multiply 49 by -3:
[tex]\[
-3 \times 49 = -147
\][/tex]
The expression now is:
[tex]\[
-147 + 25
\][/tex]
4. Add 25 to -147:
Finally, add 25 to -147:
[tex]\[
-147 + 25 = -122
\][/tex]
So, the value of the expression [tex]\(-3b^2 + 25\)[/tex] when [tex]\(b = 7\)[/tex] is [tex]\(-122\)[/tex].
Therefore, the correct answer is:
B. -122
