Answer:
4. 19+x=23 when x=4
5. (5×8a)+(5×2) is an equivalent to 5(8a+2)
6. 5x=45 x=45/5=9
2x-8=12 2x=20 x=10
40=25+3x 3x=35 x=15
7. 2+(-2) is equal to zero
7-(-10) is positive
