Question 1 :
Solve for r :
7r + 7 = 13 + 6r
Question 2 :
Solve for x :
13 - 4x = 1 - x
Question 3 :
Solve for x.
-7x - 3x + 2 = -8x - 8
Question 4 :
Solve for b :
-14 + 6b + 7 - 2b = 1 + 5b
Question 5 :
Solve for x :
-6x - 20 = -2x + 4(1 - 3x)
Question 6 :
Solve for n :
4n - 40 = 7(-2n + 2)
Question 7 :
Solve for x :
-31 - 4x = -5 - 5(1 + 5x)
Question 8 :
Solve for x
-3(x - 1) + 8(x - 3) = 6x + 7 - 5x
Question 9 :
Solve for x :
4(-8x + 5) = -32x - 26
Question 10 :
Solve the following equation :
(1/2)(8y - 6) = 5y - (y + 3)
Question 11 :
Solve the following system of linear equations using elimination method.
3x + 2y = 8
7x - 2y = 12
Question 12 :
Solve the following system of linear equations substitution method.
y = 7x - 3
x + 3y = 13
Question 13 :
The denominator of a fraction exceeds the numerator by 5. If 3 be added to both, the fraction becomes 3/4. Find the fraction.
Question 14 :
The total number of students in a school is 501. If the number of boys is equal to 3 more than twice the number of girls, find the number of boys and girls.
1. Answer :
7r + 7 = 13 + 6r
Subtract 6r from each side.
r + 7 = 13
Subtract 7 from each side.
r = 6
2. Answer :
13 - 4x = 1 - x
Add 4x to each side.
13 = 1 + 3x
Subtract 1 from each side.
12 = 3x
Divide each side by 3.
4 = x
3. Answer :
-7x - 3x + 2 = -8x - 8
Combine the like terms.
-10x + 2 = -8x - 8
Add 10x to each side.
2 = 2x - 8
Add 8 to each side.
10 = 2x
Divide each side by 2.
5 = x
4. Answer :
-14 + 6b + 7 - 2b = 1 + 5b
Combine the like terms.
4b - 7 = 1 + 5b
Subtract 4b from each side.
-7 = 1 + b
Subtract 1 from each side.
-8 = b
5. Answer :
-6x - 20 = -2x + 4(1 - 3x)
Simplify.
-6x - 20 = -2x + 4 - 12x
-6x - 20 = 4 - 14x
Add 14x to each side.
8x - 20 = 4
Add 20 to each side.
8x = 24
Divide each side by 8.
x = 3
6. Answer :
4n - 40 = 7(-2n + 2)
Simplify.
4n - 40 = -14n + 14
Add 14n to each side.
18n - 40 = 14
Add 40 to each side.
18n = 54
Divide each side by 18.
n = 3
7. Answer :
-31 - 4x = -5 - 5(1 + 5x)
Simplify.
-31 - 4x = -5 - 5 - 25x
-31 - 4x = -10 - 25x
Add 21x to each side.
-31 + 21x = -10
Add 31 to each side.
21x = 21
Divide each side by 21.
x = 1
8. Answer :
-3(x - 1) + 8(x - 3) = 6x + 7 - 5x
Simplify.
-3x + 3 + 8x - 24 = x + 7
5x - 21 = x + 7
Subtract x from each side.
4x - 21 = 7
Add 21 to each side.
4x = 28
Divide each side by 4.
x = 7
9. Answer :
4(-8x + 5) = -32x - 26
Simplify.
-32x + 20 = -32x - 26
Add 32x to each side.
20 = -26
In the final step of solving the given equation, the variable 'x' is no more.
And also, the result '20 = -26' is false.
So, the given equation has no solution.
10. Answer :
(1/2)(8y - 6) = 5y - (y + 3)
Simplify both sides.
4y - 3 = 5y - y - 3
4y - 3 = 4y - 3
Subtract 4y from each side.
-3 = -3
In the final step of solving the given equation, the variable 'x' is no more.
And also, the result '-3 = -3' is true.
Because the result is true, the given equation is true for all real values of x.
So, the given equation has infinitely has many solutions.
11. Answer :
3x + 2y = 8 ----(1)
7x - 2y = 12 ----(2)
In the above two equations, the coefficient of y-terms are same with different signs.
By adding those two equations, you can eliminate y-terms.
(1) + (2) :
10x = 20
Divide both sides by 10.
x = 2
Substitute x = 2 in (1).
3(2) + 2y = 8
6 + 2y = 8
Subtract 6 from both sides.
2y = 2
Divide both sides by 2.
y = 1
Therefore, the solutions for the given system of linear equations are
x = 2 and y = 1
12. Answer :
y = 7x - 3 ----(1)
x + 3y = 13 ----(2)
Substitute y = 7x - 3 in (1).
x + 3(7x - 3) = 13
Use Distributive Property.
x + 21x - 9 = 13
22x - 9 = 13
Add 9 to both sides.
22x = 22
Divide both sides by 22.
x = 1
Substitute x = 1 in (1).
y = 7(1) - 3
y = 7 - 3
y = 4
Therefore, the solutions for the given system of linear equations are
x = 1 and y = 4
13. Answer :
Let x be the numerator.
Since the denominator of the fraction exceeds the numerator by 5, the fraction is
= x/(x + 5) ----(1)
Given : If 3 be added to both, the fraction becomes 3/4.
From the above information, we have
(x + 3)/(x + 5 + 3) = 3/4
Simplify.
(x + 3)/(x + 8) = 3/4
4(x + 3) = 3(x + 8)
4x + 12 = 3x + 24
x = 12
Substitute x = 12 in (1).
fraction = 12/(12 + 5)
= 12/17
So, the required fraction is 12/17.
14. Answer :
Let b be the number of boys and g be the number of girls in the school.
From the given information,
b + g = 501 ----(1)
b = 2g + 3 ----(2)
We can solve the above system of linear equations in two variables using substitution method.
Substitute b = 2g + 3 in (1).
2g + 3 + g = 501
3g + 3 = 501
Subtract 3 from both sides.
3g = 498
Divide both sides by 3.
g = 166
Substitute g = 166 in (2).
b = 2(166) + 3
b = 332 + 3
b = 335
Therefore,
number of boys = 335
number of girls = 166
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