tolong bantu dong....

1) a. Luas = (10+15)×8 = 25 × 8 = 200cm²
b. Luas = (12+18)×9 = 30 × 9 = 270cm²
c. Luas = (20+25)×10 = 45×10= 450cm²
d.Luas = (18+22)×x
300cm² = 40×x
300cm² = 40x
40x = 300cm²
x = 300cm² : 40
=7,5 cm
e.Luas = (22+23)×x
450 = 45x
x = 450 : 45
= 10 cm
f.Luas = (18+x)×25
500 = 550 + 25x
-25x = 550-500
= 50
x = 50 : -25
= -2
klo btuh bntuan lgi...krim psan ajh k kka ya de...