Jawaban:

Penjelasan dengan langkah-langkah:

p = (3x + 4) cm

l = (x + 3) cm

K = 30 cm

\begin{gathered}k = 2(p + l) \\ 30 = 2(3x - 4 + x + 3) \\ 30 = 2(4x - 1) \\ 30 = 8x - 2 \\ 30 + 2 = 8x \\ 32 = 8x \\ \frac{32}{8} = x \\ 4 = x\end{gathered}k=2(p+l)30=2(3x−4+x+3)30=2(4x−1)30=8x−230+2=8x32=8x832=x4=x

panjang persegi panjang

\begin{gathered}p = 3x + 4 = 3(4) + 4 = 12 + 4 = 16 \: cm \\ \end{gathered}p=3x+4=3(4)+4=12+4=16cm

lebar persegi panjang

l = x + 3 = 4 + 3 = 7 \: cml=x+3=4+3=7cm

Luas persegi panjang

\begin{gathered} = p \times l \\ = 16 \times 7 \\ = 112 \: {cm}^{2} \end{gathered}=p×l=16×7=112cm2