Solve x2 = 14x – 49.

I'm really confused.... It has to be factored and I can't figure out how... :( Please help!

Question

Solve x2 = 14x – 49.

I'm really confused.... It has to be factored and I can't figure out how... :( Please help!

phi · Answer

can you put it into "standard form" ?

anonymous · Answer

x2 - 14x - 49 = 0 or -x2 + 14x - 49 = 0

anonymous · Answer

* x2 - 14x + 49 = 0

anonymous · Answer

That looks good.  Could you use the Quadratic formula from here?

phi · Answer

yes.

now list all the ways to multiply 2 numbers that give you 49
1,49
7,7

those are your only choices
which pair can be added to give you 14 ?

anonymous · Answer

7 and 7 but they don't multiply to -49.... You would have to multiply -7 and 7 and that would give you a sum of 0....

phi · Answer

x^2 - 14x + 49 = 0 

the + on the 49 means the factors will have the same sign
the - on the 14 means the larger factor is -
that means both are -

anonymous · Answer

okay

phi · Answer

I am not sure why you say ***7 and 7 but they don't multiply to -49

unless you were not looking at the equation in standard form, where you have a +49

anonymous · Answer

I was looking at the other version of standard form... You can either move the x2 or the other part and I looked at the wrong one.... So x=7?

phi · Answer

yes, x=7

as a check:
x^2 = 14x – 49  ?
7*7 = 14*7 - 49 ?
49 = 98 -49 ?
49 = 49  yes. it worked