Question

Ques. if a is real and 1 + a + a2 + a3 = 40, then a is equal to:

Answer 1

Answer:

a is equal to 3

a=3

1+3+9+27=40

so the answer is 3

Answer 2

Q. If a is real and 1+a+a²+a³= 40, then a is equal to: ?

Ans. a = 3

Given:  1+a+a²+a³=40

To Find: The value of a

Solution:

1+a+a²+a³=40

1+a+a²+a³- 40= 0  (moving constant to the left)

a³+a²+a -39 = 0     (reorder the expression)

factor: (a-3) (a²+4a+13) = 0

separate the equation into two possible cases:

∵ a-3= 0 or a²+4a+13 = 0

∵ a=3  or  13+4a+a² = 0

∴ a = 3  or  a = no real solution

Either a=3 or a does not have a value

Hence, a = 3

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