Answer:
Step-by-step explanation:
In order to add or subtract numbers in scientific notation, the powers of ten must have the same exponent. In this caes the diameter of an average human body cell is a power of -4 and the diameter of a plant cell is a power of -3. In order to add them, we can move the decimal over for the body cell diameter:
Add the two values: 
Answer:
28. m<A=20°, m<B=70°
32. m<A=103°, m<B=77°
Step-by-step explanation:
complementary angle=a+b=90°
supplementary angle=a+b=180°
28. A+B=90°
5x+17x+2=90°
22x+2=90°
22x=90-2
22x=88
22x/22=88/22
x=88/22=<u>4</u>
m<A=5x=5*4=<u>20°</u>
m<B=17x+2=17*4+2=68+2=<u>70°</u>
<u>Check</u>
A+B=90°
20+70=90°
<u>90°=90°</u>
32. A+B=180°
x+11+x-15=180°
2x-4=180°
2x=180+4
2x=184
2x/2=184/2
x=184/2
x=<u>92</u>
m<A=x+11=92+11=<u>103°</u>
m<B=x-15=92-15=<u>77°</u>
<u>Check</u>
A+B=180°
103+77=180°
<u>180°=180°</u>
X/4+7=12
x/4+7-7=12-7
x/4=5
x/4*4=5*4
x=20
Y=-3
If a line is ever completely horizontal, it's going to be y = a normal value, no X. x = a normal value is going to be a vertical line.
