Question

cacule o 15 termo da pa a7=-20 e r3/2 me ajudem pfvr

Answer 1

$a15~?~~~~~~a7=-20~~~~~r= \frac{3}{2}$

$a7=a1+6r$
$-20=a1+\not 6. \frac{3}{\not2}$
$-20=a1+3.3$
$-20=a1+9$
$a1= -20-9$
$\boxed{a1=-29}$

$\boxed{15 = a1+14r}$
$a15 = -29 + \not14. \frac{3}{\not2}$
$a15 = -29+7.3$
$a15= -29+21$
$\boxed {a15 = -8 }$