What are the solutions for a^2 - a - 30 = 0?
A) 6 and -5
B) 6 and 5
C) 5 and -6
D) -6 and -5
2007-06-01 02:51:07 · 7 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Try to think of two numbers that multiply to -30 and add to -1 (one will be negative, the other will not).
2007-06-01 02:54:00 · answer #1 · answered by Joy M 7 · 1⤊ 1⤋
a^2 - a - 30 = (a-6)(a+5) = 0
Case 1
(a-6) = 0
Therefore a = 6
Case 2
(a+5) = 0
Therefore a = -5.
Conclusion : a= 6 or -5 #
The answer's A.
2007-06-01 10:12:07 · answer #2 · answered by English Learner 2 · 0⤊ 0⤋
factor the equation:
a^2 - a - 30 = 0
(a - 6)(a + 5)
a=6, a= -5
the answers is A
2007-06-01 10:07:45 · answer #3 · answered by pretty girl make grave 2 · 0⤊ 0⤋
The "quick" way to solve this, since they gave you choices, is to try them.
try 6
6^2 - 6 - 30 = 0? 36 - 36 = 0, so 6 is one answer.
try -5
(-5)^2 -(-5) - 30 = 0? 25 +5 - 30=0, so -5 is the other.
So, A is the correct choice.
If you weren't given choices, you could try to factor it, or apply the quadratic formula.
2007-06-01 10:00:10 · answer #4 · answered by Jason K 2 · 1⤊ 1⤋
a^2-a-30=0
=> a^2-6a+5a-30=0
=>a(a-6)+5(a-6)=0
=>(a-6)(a+5)=0
=>a=6 or -5
2007-06-01 10:05:28 · answer #5 · answered by sailendra k 2 · 0⤊ 0⤋
a^2 - a - 30 = 0
First factor
(a - 6)(a + 5) = 0
Then solve for a
a = 6, a = -5
.
2007-06-01 09:55:24 · answer #6 · answered by Robert L 7 · 1⤊ 1⤋
a^2 - a - 30 = 0
Break down the equation
(a +5) (a - 6) = 0
The solutions are:
a = -5
a = 6
2007-06-01 10:02:17 · answer #7 · answered by Redhawkphl 2 · 1⤊ 1⤋