Tolong bantu no 6 7 dan 8

6.
diketahui:
t(tinggi kerucut) = 16 cm
r(jari-jari alas) = 12 cm
ditanya:
a. s(garis pelukis) = ?
b. LP(Luas Permukaan) = ?

a.
s = √(t² + r²)
= √(16² + 12²)
= √(256 + 144)
= √400 = 20 cm

b.
LP = πr(r + s)
= 3,14 × 12(12 + 20)
= 37,68(32)
= 1205,76 cm²

7.
rumus persamaan garis: y = m1x + c
y = 4x + 9
maka, m1 = 4

sejajar : m1 = m2, maka m2 = 4

(-5, 3) misalkan (x1, y1)

rumus mencari persamaan garis:
y - y1 = m2(x - x1)
y - 3 = 4(x - (-5))
y - 3 = 4(x + 5)
y = 4x + 20 + 3
y = 4x + 23

8.
(2x - y)/3 = 2 1/3
[(2x - y)/3 = 7/3] × 3
2x - y = 7 ......(1)

[(x + 2y + 1)/2 = 6] × 2
x + 2y + 1 = 12
x + 2y = 12 - 1
x + 2y = 11 ......(2)

eliminasikan (1) dan (2):
2x - y = 7 | × 2
x + 2y = 11 | × 1

4x - 2y = 14
x + 2y = 11
_________ +
5x = 25
x = 25/5 = 5

masukkan x = 5 ke (1)
2x - y = 7
2(5) - y = 7
10 - y = 7
10 - 7 = y
3 = y

HP = {5, 3}

maaf kalau salah
semoga membantu