Question

which of the following is not true
a. (a+b)^2= a^2+2ab+b^2
b. a^2+4a+4=(a+2)^2
c. a^2-2ab+b^2=(a-b)^2
d. a^2-6ab-9b^2=(a-3b)^2
e. (3a+2b)^2+9a^2+12ab+4b^2

Answer 1

when you do, \(\huge (a-b)^2\)
the last term, \(\large b^2\) is positive ,
\(\large (a-b)^2=a^2-2ab \huge+ b^2\)

Answer 2

but that ones true

Answer 3

which one isnt true

Answer 4

try d, and see whether you get left side = right side...

Answer 5

i got a^2+9b^2

Answer 6

actually, its a^2-6ab+9b^2
but the point is its +9b^2 and not -9b^2
so, its d