bantu jawab please...

PGL

Garis a melalui (0 , 3) dan (4 , 0)

Persamaannya :
ax + by = ab
3x + 4y = 3 × 4
3x + 4y = 12
4y = -3x + 12
y = -¾ x + 3
[tex] \mathrm{m_a} = - \frac34 [/tex]

Garis b melalui (4 , 0)

Garis a dan b tegak lurus , maka berlaku :
[tex] \mathrm{m_a \cdot m_b} = -1 \\
- \frac34 \cdot \mathrm{m_b} = -1 \\
\mathrm{m_b} = \frac43 \\
\\
Persamaannya \ : \\
y=\mathrm{m_b}(x-x_1)+y_1 [/tex]
y = ⁴/₃(x - 4) + 0
y = ⁴/₃ x - ¹⁶/₃ [C]

Pers grs a melalui ttk (0,3) dan (4,0)
m = (3-0)/(0-4)
m = - 3/4

Karena pers grs b tegak lurus pers grs a maka mb x ma = -1
Jadi mb = 4/3

y-y1 = m(x-x1)
y - 3 = 4/3(x - 0)
y - 3 = 4/3 x
y = 4x/3 + 3