Suppose the number of 2 hours lessons are x and 1 hour lessons are y; thus,
2x+y=25
50x+30y=690
to get the values of x and y we solve the quadratic equation given;
from the top equation:
y=25-2x.......i
substituting i in our second equation we get:
50x+30(25-2x)=690
50x+750-60x=690
-10x=-60
thus;
x=6
hence we conclude that the number of 2 hours classes are 6 hours
Answer: 6
Step-by-step explanation: First, let's find the least common denominator between the 2 fractions, which is 4. Now let's multiply 9/2 by 2 to get the denominator of 4. Once you multiply the numerator and denominator by 2 you would get 18/4. So now the problem turns into how many 3/4 goes into 18/4. We know that 3/4 x 6 = 18/4. So the final answer is 6.
Answer:
see below
Step-by-step explanation:
4(5n-7)+10n+2
Distribute
20n -28 +10n+2
Combine like terms
30n-26
Assuming you meant =
4(5n-7)=10n+2
Distribute
20n -28 =10n+2
Subtract 10n from each side
20n-10n-28 = 10n-10n+2
10n-28 =2
Add 28 to each side
10n-28+28=28+2
10n=30
Divide by 10
10n/10 =30/10
n=3
9(x+3)=4x-3
Distribute
9x+27 = 4x-3
Subtract 4x from each side
9x-4x+27 = 4x-4x-3
5x +27 =-3
Subtract 27 from each side
5x+27-27 = -3-27
5x = -30
Divide by 5
5x/5 = -30/5
x=-6
2(12-8x)=x-11x
Combine like terms
2(12-8x) = -10x
Divide by 2
12-8x = -5x
Add 8x to each side
12-8x+8x = -5x+8x
12 = 3x
Divide by 3
12/3 =3x/3
4=x
Answer:
x = 7 , y = 2
Step-by-step explanation:
It is a linear equation in 2 variables so it can have infinite solutions
Put x=7 Then,
7 - 3y = 1
-3y = 1-7
-3y = -6
y = -6/-3 = 6/3
y = 2