1) 9x + 4x = -26;

x(9 + 4) = -26;

13x = -26;

x = -26 : 13;

x = -2;

2) 11x + 7x - 24x = 42;

x(11 + 7 - 24) = 42;

-6x = 42;

x = 42 : (-6);

x = -7.