Answer:
3: 
4: 
Step-by-step explanation:
Question 3 can be re-written as:

which equals:

Question 4 can be re-written as:

Doing the first 2 brackets gives us:

Expanding these two:

Simplifying it:

Answer:
11x -8y = -9
Step-by-step explanation:
8x-4y=-4
-3x+4y=5
Subtract the second equation from the first
8x-4y=-4
-(-3x+4y=5)
-----------------------------
Distribute the minus sign
8x-4y=-4
+(3x-4y=-5)
-----------------------------
11x -8y = -9
Answer:
19. D
20. A
Step-by-step explanation:
19. Tan= opp/adj
20. Sin= opp/hyp
Just subtract but take care of the power or else you can come up with wrong results !
so first make the power same ;
for Jupiter = 1.898× 10(27) = 18.98 × 10(26)
for Saturn = 5.68×10(26)
so now subtract = (18.98-5.68) × 10(26)
= 13.3 × 10(26)
so the answer is 13.3 ×10(26)
or, 1.33× 10(27)