Answer:
40
Step-by-step explanation:
1) the basic is: the mass of the salt before pure water is added = the mass of the salt after the pure water is added;
2) the mass of the salt before pure water is added was:
40*0.1;
3) the mass of the salt after pure water is added is:
(40+w)*0.05, where w - the required mass of pure water;
4) if the mass of the salt is the same, then:
40*0.1=(40+w)*0.05;
5) if to evaluate the equation:
(w+40)*0.05=4; ⇔ w+40=80; ⇔ w=40 gr.
Answer:
∠ AFE = 80°
Step-by-step explanation:
Since BD is a straight line , then
∠ AFB + ∠ AFE + ∠ EFD = 180°, that is
50° + ∠ AFE + 50° = 180°
100° + ∠ AFE = 180° ( subtract 100° from both sides )
∠ AFE = 80°
Answer:
17
Step-by-step explanation:
unless im missing something this is just addition
Answer:
C. = 1 and 5
D. = 4 and 5
B. = 2 and 7
A. = 3 and 5
Step-by-step explanation:
Answer : number 4 is a dependent system
Explanation:
If we look at number 4
2x+2y=6 , y= -x+3
2(x+y)=6
x+y=6/2=3
y=-x+3
Now we see that the two equation have the same slope (-x) and the same y intercept (+3) we can clearly say that these 2 equation are dependent because it has infinite solution