In $\text{IEEE-754}$ single precision formate ($32$ bit) binary number is represented as:
$\text{S(1 bit) E(8 bit) M(23 bits)}$,
with implicit normalization and exponent is represented with $\text{Excess-127}$ code.
So here,
- Sign bit= $1$ $\Rightarrow$ number is negative.
- Exponent bit= $10000111=135 \Rightarrow 135-127=8$
- Mantissa bit= $11100000000000000000000 = 1.111 \rightarrow(\text{implicit normalized form})$
$\therefore V= (-1)^S*1.M*\text{Base}^{E-127}$
$\Rightarrow V=(-1)^1*1.111*\text{2}^{135-127}$
$\Rightarrow V= -1*(1.111)_2*\text{2}^8$
$\because (1.111)_2=(1.875)_{10}$
$\therefore V= -1* 1.875*256= -480$
So correct decimal value is $-480.$