数研出版：これからの数学１

p.99 問1\(\begin{split}~~~x=1\end{split}\)

p.102 問1左辺に \(x=10\) を代入すると、
\(\begin{split}~~~10-3=7\end{split}\)
よって、右辺の \(7\) と等しくなり、\(x=10\) が方程式の解である

p.102 問2\(\begin{split}{\small (1)}~x=7\end{split}\)　　\(\begin{split}{\small (2)}~x=-4\end{split}\)

p.102 問3\(\begin{split}{\small (1)}~x=-7\end{split}\)　　\(\begin{split}{\small (2)}~x=3\end{split}\)

p.103 問4\(\begin{split}{\small (1)}~x=8\end{split}\)　　\(\begin{split}{\small (2)}~x=-24\end{split}\)
\(\begin{split}{\small (3)}~x=-50\end{split}\)

p.103 問5\(\begin{split}{\small (1)}~x=4\end{split}\)　　\(\begin{split}{\small (2)}~x=3\end{split}\)

---

\(\begin{split}{\small (3)}~x=-12\end{split}\)　　\(\begin{split}{\small (4)}~x=-\frac{\,3\,}{\,4\,}\end{split}\)

p.103 問6\(\begin{split}{\small (1)}~x=9\end{split}\)　　\(\begin{split}{\small (2)}~x=-15\end{split}\)
\(\begin{split}{\small (3)}~x=-8\end{split}\)　　\(\begin{split}{\small (4)}~x=-6\end{split}\)
\(\begin{split}{\small (5)}~x=7\end{split}\)　　\(\begin{split}{\small (6)}~x=18\end{split}\)

p.105 問1\(\begin{split}{\small (1)}~x=10\end{split}\)　　\(\begin{split}{\small (2)}~x=-6\end{split}\)

---

\(\begin{split}{\small (3)}~x=-\frac{\,4\,}{\,3\,}\end{split}\)　　\(\begin{split}{\small (4)}~x=11\end{split}\)

p.105 問2\(\begin{split}{\small (1)}~x=2\end{split}\)　　\(\begin{split}{\small (2)}~x=-4\end{split}\)
\(\begin{split}{\small (3)}~x=6\end{split}\)　　\(\begin{split}{\small (4)}~x=-10\end{split}\)

---

\(\begin{split}{\small (5)}~x=-\frac{\,11\,}{\,5\,}\end{split}\)　　\(\begin{split}{\small (6)}~x=5\end{split}\)

p.106 問3\(\begin{split}{\small (1)}~x=2\end{split}\)　　\(\begin{split}{\small (2)}~x=4\end{split}\)
\(\begin{split}{\small (3)}~x=-3\end{split}\)　　\(\begin{split}{\small (4)}~x=2\end{split}\)

---

\(\begin{split}{\small (5)}~x=0\end{split}\)　　\(\begin{split}{\small (6)}~x=-\frac{\,5\,}{\,2\,}\end{split}\)

p.107 問4\(\begin{split}{\small (1)}~x=3\end{split}\)　　\(\begin{split}{\small (2)}~x=-1\end{split}\)
\(\begin{split}{\small (3)}~x=-2\end{split}\)　　\(\begin{split}{\small (4)}~x=1\end{split}\)

p.108 問5\(\begin{split}{\small (1)}~x=9\end{split}\)　　\(\begin{split}{\small (2)}~x=-5\end{split}\)
\(\begin{split}{\small (3)}~x=7\end{split}\)　　\(\begin{split}{\small (4)}~x=1\end{split}\)

p.109 問6\(\begin{split}{\small (1)}~x=-3\end{split}\)　　\(\begin{split}{\small (2)}~x=-12\end{split}\)
\(\begin{split}{\small (3)}~x=6\end{split}\)　　\(\begin{split}{\small (4)}~x=9\end{split}\)

p.109 問7\(\begin{split}{\small (1)}~x=3\end{split}\)　　\(\begin{split}{\small (2)}~x=-3\end{split}\)

---

\(\begin{split}{\small (3)}~x=\frac{\,1\,}{\,2\,}\end{split}\)　　\(\begin{split}{\small (4)}~x=12\end{split}\)

---

\(\begin{split}{\small (5)}~x=-2\end{split}\)　　\(\begin{split}{\small (6)}~x=-\frac{\,7\,}{\,5\,}\end{split}\)

p.111 問1\(\begin{split}~~~x~:~24=2~:~3\end{split}\)
比例式の性質より、
\(\begin{eqnarray}~x {\, \small \times \,} 3&=&24 {\, \small \times \,}2
\\[2pt]~~~3x&=&48
\\[2pt]~~~x&=&16
\end{eqnarray}\)

p.111 問2\(\begin{split}{\small (1)}~x=12\end{split}\)　　\(\begin{split}{\small (2)}~x=45\end{split}\)

p.111 問3\(\begin{split}~~~x=5\end{split}\)

p.113 問1\(~~~50\) 円

p.114 問2\(~~~1000\) 円

p.115 問3\(~~~\)絵はがき１枚 \(70\) 円
\(~~~\)最初に持っていた金額 \(1000\) 円

p.117 問4\(~~~5\) 分後
\(~~~\)家から \(1200~{\rm m}\)

p.117 問5姉が追いつく前に弟が駅につく