SAT practice question: Rational equations (3^2 = a-1, so a=10)

I

Illvoices

Junior Member
Joined
Jan 13, 2017
Messages
116
(3)2 = a-1
a=10

Could someoneasily tell me how'd the three squared turned into a ten? I mean wasen't the negative plus the negative suppose you give you a negative.
 
Illvoices said:
(3)2 = a-1
a=10

Could someoneasily tell me how'd the three squared turned into a ten? I mean wasen't the negative plus the negative suppose you give you a negative.
Click to expand...
Just because a=10 does not mean 32 =10. 32 = 9, so the initial equation because 9 = a-1 or a-1 =9. This equations ask the question what - 1 = 9. Since what = 10 (since 10-1=9) and what is a, we have a=10.
 
Illvoices said:
(3)2 = a-1
a=10

Could someoneasily tell me how'd the three squared turned into a ten? I mean wasen't the negative plus the negative suppose you give you a negative.
Click to expand...
\(\displaystyle 3^2 = a - 1 \implies 9 = a - 1 \implies 9 + 1 = a - 1 + 1 \implies 10 = a + 0 \implies a = 10.\)
 
Illvoices said:
I understand it now. Thank you
I wasn'the isolating the a correctly.
Click to expand...
No need to isolate the a.

9 = a - 1.
I am sure that you can fill in the blank in 9 = _ - 1.

Of course the answer is 10, since 9 = 10 - 1, so a = 10.

One makes more mistakes doing things mechanically then compared to doing it by thinking.

When the equation is as simple as your equation then you can just put a box for a and conclude it must be 10.
 
You must log in or register to reply here.
Top