minta tolong dikerjakan ya no. 8,9,10 ya

8. P = 2x-1 , l = x+2
a. Keliling
2p + 2l
2(2×-1) + 2(x+2)
4x-2 + 2x + 4
4x+2x -2+4
6x +2

b. 6x + 2 = 50
6x = 50 - 2
6x = 48
X = 8

C. Panjang
2x-1
2(8) - 1
16- 1 = 15

Lebar
X + 2
8 + 2 = 10

9. Dik :
X = -2 , y = 4
5x^2 - xy + 3y^2
5(-2)^2 - (-2 • 4 ) + 3(4)^2
5(4) - (-8) + 3(16)
20 + 8 + 48 = 76

10. Dik :
a = -1 , b = 3
a^4 + 4a^3 b + 6a^2 b^2 + 4ab^3 + b^4
-1^4 + 4(-1)^3• 3 + 6(-1)^2•3^2 + 4(-1)• 3^3 + 3^4
1 + 64 • 3 + 36•9+(-4) • 27 + 81
1 + 192 + 324 + (-108) + 81
= tinggal jumlahin