ada yang bisa jawab ini tolong ya

8) y = x^2 + bx + 4, y = 3x + 4
y = y
x^2 + bx + 4 = 3x + 4
x^2 + (b - 3)x = 0
Karena menyinggung maka D = 0
b^2 - 4ac = 0
(b - 3)^2 - 4(1)(0) = 0
(b - 3)^2 = 0
b - 3 = 0
b = 3

9) Santi = S, Elis = E, Andi = A
S = 4 + E
E = 3 + A => A = E - 3

S + E + A = 58
(4 + E) + E + (E - 3) = 58
3E + 1 = 58
3E = 57
E = 19

S + E + A = 58
S + A = 58 - E = 58 - 19 = 39

10) x + y + z = 75

x = 5 + y + z => y + z = x - 5
x + y + z = 75
=> x + (x - 5) = 75
=> 2x = 80
=> x = 40