2x+y=9
3x+5y=19
I will do this problem in 2 ways. I.)Substitution II.)Elimination
Solution I.) Substitution
We can subtract 2x from both sides in the first equation.
y=9-2x
Now we can substitute the y in the second equation with 9-2x
3x+5(9-2x)=19
-7x+45=19
-7x=-26
x=26/7
y=9-2(26/7)=11/7
Solution II.)Elimination
We can multiply both side of first equation by 5 to get a 5y in both equations.
10x+5y=45
Now because both are positive 5y we just need to do simple subtraction of the 2 equation, each side respectively.
(10x+5y)-(3x+5y)=45-19
7x=26
x=26/7
2*26/7+y=9
y=11/7
Ultimately you get the same answer, both are viable methods, some problems are faster with one method but I recommend mastering both since they are very useful.
Answer:
The answer is A.
Step-by-step explanation:
So we have the two equations:
To make a substitution of the second equation into the first equation, we need to isolate the <em>y </em>variable in the second equation. Thus:
Now, we can substitute this into the first equation. Therefore:
Answer:
Step-by-step explanation:
1a. 25/50 =x/100
25*100= 2500/50= 50
A= 50%
1b. 35/40 = x/100
35*100= 3500/40= 87.5
A=87.5%
2a. 15/20= x/100
20*5= 100; 15*5= 75
A=75%
2b. 25/70= x/100
25*100= 2500/70= 35.71
A=35.71
3a. 15/80= x/100
15*100= 1500/80=18.75
A=18.75%
3b. 30/60= x/100
30/60= 1/2;1/2=0.5;0.5= 50%
A=50%
4a. 70/80 =x/100
70*100=7000/80 =87.5
A=87.5
4b.30/60 = 50% ( same as question #3b)
