Given the Arithmetic sequence [math] a_1,a_2,a_3,a_4 39, 45, 51, 57, \dots [/math]What is the value of [math] a_{42}?[/math] Given the Arithmetic sequence [math] a_1,a_2,a_3,a_4, 45,51,57,63,\dots [/math], What is the value of [math] a_{34}?[/math]