Answer:
A) [tex]9b^2 + 3a - 10[/tex]
Step-by-step explanation:
The given choices are
A) 9b^2 + 3a - 10
B) a^2 - 20 - 3b
C) 3(a - 2) - a + a 6b
D) 9b + ab
Now, we need to evaluate each expression and see which one gives 6 as result.
We know that [tex]a=5[/tex] and [tex]b=\frac{1}{3}[/tex]
A)
[tex]9b^2 + 3a - 10=9(\frac{1}{3} )^{2}+3(5)-10=9 \times \frac{1}{9}+15-10=1+5=6[/tex]
Choice A is part of the right answer, because is equal to 6.
B)
[tex]a^2 - 20 - 3b=(5)^{2}-20-3(\frac{1}{3} )=25-20-1=5-1=4[/tex]
Choice B is not part of the right answer.
C)
[tex]3(a - 2) - a + a 6b=3(5-2)-5+5(6)(\frac{1}{3})=3(3)-5+10=9+5=14[/tex]
Choice C is not part of the answer.
D)
[tex]9b + ab=9(\frac{1}{3})+5(\frac{1}{3} )=3+\frac{5}{3}=\frac{9+5}{3}=\frac{14}{3}[/tex]
Therefore, the only expression which is equal to 6 when a = 5 and b = 1/3 is choice A.
