102. 12+90=102.
90
90+x+72+30 = 180. If you add 90+72+30, you get 192. But to get 180 you have to subtract 12. 90+(-12)+72+30 =180 if x is -12
702
7.8 + 12 = 19.8
90
102
-90
385
480
4x + 4 + 5x - 22 = 90 combined like terms 9x - 18 = 90 +18 +18 9x = 108 /9 /9 divide by 9 on both sides x = 12 plug in and check (4 * 12) + 4 + (5 * 12) - 22 = 90 48 + 4 + 60 -22 = 90 90 = 90
270
525. 5 + 4 = 9 + 67 = 73 + 98 = 171 + 12 = 183 + 34 = 217 + 11 = 229 + 51 = 280 + 90 = 370 + 47 = 417 + 8 = 525.