Let
x--------> the number
we know that
11²=121
12²=144
then
x² must be greater than 121 and less than 144
case a) <span>√115
if x=</span><span>√115
then
x</span>²=115-------> is not greater than 121
case b) <span>√121
</span>if x=√121
then
x²=121-------> is not greater than 121
case c) <span>√136
</span>if x=√136
then
x²=136-------> is greater than 121 and is less than 144------> is ok
case d) <span>√150
</span>if x=√150
then
x²=150------> is not less than 144
therefore
the answer is
√136
Quadratic is in the form
ax^2+bx+c=0
so distribute and stuff and simplify
remember
a(b+c)=ab+ac
(x+2)^2+5(x+2)-6=0
remember order of opertaions
(x+2)(x+2)+5(x+2)-6=0
x^2+4x+4+5x+10-6=0
add like terms
x^2+9x+8=0
