P = 2(a + b)
P1 = a + d/2 + d/2 = a + d, где d - диагональ
P2 = b + d/2 + d/2 = b + d
a + d = 4/7 * 2(a + b)
a + d = 8a/7 + 8b/7
d = a/7 + 8b/7
P2 = b + d = b + a/7 + 8b/7 = 18a/14 + 18b/14
30b/14 + 2a/14 = 18a/14 + 18b/14
12b/14 = 16a/14
12b = 16a
3b = 4a
b = 4a/3
Ответ: стороны относятся как 3:4
1) 7x/15=21/5 x=9
2) 6.1y=3.05*0.6=1.83 y=0.3
3) 22/435*x=22/87 x=5
5х=7-10
х=-3/5
2х=-6-4
х=-5
9х=15
х=15/9=5/3=1 2/3
5х=17-3
х=14/5=2 4/5
-3х+5х+17х-2х=29+13-26-10
17х=6
х=6/17
125×4+125×6=500+750=1250
315×2+315×8=630+2520=3150
241×5+241×5=1205+1205=2410
418×3+418×7=1254+2926=4180
314×3+314×7=945+2205=3150
829×1+829×9=829+7461=8290