Question

what number must you add in order to make x^2-4x=1 a complete square?

Answer 1

I need helpe with the process.

Answer 2

help

Answer 3

gblover, patiently go through this write-up and post ur doubts...we'll clear it.

see basically the logic is to bring it to the form (x+b)^2=x^2+b2+2xb, so for getting this factorisation, see appropriately what to add.
observe that the x term has co-efficient 2b and so if u hav a b^2 term u will form the complete square by the formula rite? so u add b^2

Answer 4

here the 2b term is -4 and hence the b term is 2b=-4 and so b=-2.
so u need to add (-2)^2 =4 get it?

Answer 5

ok the process goes like this
you have
\[x^2+4x=1\] the coefficient of the x term is 4
1) half of 4 is 2
2) 2 squared is 4

so you add 4 to both sides and get
\[x^2+4x+4=1+4\]
\[x^2+4x+4=5\]
and the left side is a perfect square, namely
\[(x+2)^2=5\]

Answer 6

sorry i wrote + when it should have been - but the process is the same

Answer 7

so you subract 4 from both sides?