2ax = 20
x = 20/2a = 10/a **
3a + 3x = 21
3a + 3(10/a) = 21
3a/1 + 30/a = 21/1
mmc = a
3a² + 30 = 21a
3a² - 21a + 30 = 0
a² - 7a + 10 = 0
a =( 7 +-V49-40)/2
a' = (7+3)/2 = 5 ***********
a" = (7-3)/2 = 2 **********
Logo a²x + ax² vale 9 substituindo
a = 2
x =10/a
4(10/a) + 2(10/a)² =
40/a + 2( 100/a² )=
40/a + 200/a²=
1/a + 5/a² *********
a = 5
x = 10/a
25(10/a) + 5( 10/a)² =
250/a + 5( 100/a²) =
250 /a + 500/a² =
1/a + 2/a² *************