I1.1 If $100 a=35^{2}-15^{2}$, find $a$.
I1.2 If $(a-1)^{2}=3^{4 b}$, find $b$.
I1.3 If $b$ is a root of $x^{2}+c x-5=0$, find $c$.
11.4 If $x+c$ is a factor of $2 x^{2}+3 x+4 d$. find $d$.
Reference: 1987 FSG.1, 1988 FI2.2
$$
\begin{array}{l}
100 a=(35+15)(35-15)=50 \times 20=1000 \\
a=10 \\
9^{2}=3^{4 b} \\
4 b=4 \\
\Rightarrow b=1
\end{array}
$$

Put $x=1$ into the equation: $1+c-5=0$
$$
c=4
$$
$x+4$ is a factor
Put $x=-4$ into the polynomial: $2(-4)^{2}+3(-4)+4 d=0$
$$
d=-5
$$