Answer:
5. x=14
6 x=5
Explanation:
31+9x+23=180
step 1 combine like terms
54+9x=180
step 2 subtract each side by 54
9x=126
step 4 divide each side by 9
x=14
21x-9=90+27
step 1 combine like terms
21x-9=117
step 2 add 9 to each side
21x=126
step 3 divide each side by 21
x=5