Question

Solve the following word problem by using an equation and factoring. The sum of a positive number and its square is 20. What is the number?
A. 1
B. 2
C. 3
D. 4
E. 5

Answer 1

if you call the number \(x\) then you are trying to solve \(x^2+x=20\)

Answer 2

you can start with \(x^2+x-20=0\) and then factor as suggested
do you know how to factor this one?

Answer 3

@satellite73 not really ;/

Answer 4

come up with two numbers whose product is \(-20\) and that add to \(1\)
one will be positive, the other negative

Answer 5

if you don't get it let me know

Answer 6

so is the answer E?

Answer 7

i meant can you factor
the answer is not E

Answer 8

I still don't get it.

Answer 9

you can factor as \((x+5)(x-4)=0\)

Answer 10

then either \(x+5=0\) giving \(x=-5\) or \(x-4=0\) so \(x=4\)

Answer 11

since you are looking only for the positive answer, use \(x=4\)

Answer 12

So the answer is D because it's 4?

Answer 13

and we can check that it works
\[4^2=4=16+4=20\]

Answer 14

yes, it is D