please jawab ya pake cara

1.) 4x + 100 = 180
4x = 180-100
x = 80 : 4 = 20

5x+2y = 180
5.20 + 2y = 180
100 +2y = 180
2y = 180-100
y = 80:2= 40

2.) PQ = RS
3x-5 = x+9
3x-x = 9+5
2x = 14
x = 7
PQ = 3x-5 = 21-5 = 16

3.)K= (2x7) + (2x15)
=14 + 30 = 44 cm

4.) t = phytagoras 6,8,10, tingginya 8cm
L= 10x8 = 80cm²

5.) a.) L = 12 x 10 = 120cm²
b.) sisi miring = phytagoras 9,12,15 = 15cm
K= (2.15)+(2.10) = 30+20= 50cm

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