Tolong kak ini utk soal ujian

7. y = 6x + 10
m = 6

8. persamaan garis
4x + 6y = 4(-6) + 6(4)
4x + 6y = 0
atau
2x+ 3y = 0

9.
3x+y = 11
x + y = 7
-----------(-)
2x = 4
x = 2 --> y = 7-x = 7-2 = 5
Hp(x,y)= (2, 50

10.
b= buku
p= pensil
3b + 5p =6.500 ....|x2
2b + 4p = 4.800....|x3
.
6b + 10p= 13.000
6b +12p = 14.400
.....................(-)...
-2p = -1.400
p= 700

2b + 4p = 4.800
2b + 2800 = 4.800
2b = 2000
b = 1000
harga buku = 1.000 harga pensil = 700

11.
x² = y²+ z²
y² = x² - z²
z² = x² - y²