（要过程）已知3a-5b+19=0,a+8b-1=0,求：（1）-12a-9b (2)4a-26b (3)(4a+3b)×(4a+3b)-8a-6b

3a-5b = -19------1式a+8b = 1-------2式-(a+8b)*3-(3a-5b)*3 = -12a-9b= 54(3a-5b)*2-(a+8b)*2= 4a-26b= -404a+3b= 1式+2式= -18问3 = (4a+3b)^2- 2(4a+3b)= -20(4a+3b) = 360