Problems 1-10 : Simplify each expression using the laws of exponents.
Problem 1 :
2m2 ⋅ 2m3
Problem 2 :
m4 ⋅ 2m-3
Problem 3 :
(4a3)2
Problem 4 :
(x3)0
Problem 5 :
Problem 6 :
(x2y-1)4
Problem 7 :
(3x)(2x1/2)
Problem 8 :
Problem 9 :
(6ab2c3)(4b-2c-3d)
Problem 10 :
(x-ayb)3(x-3y-2)-a
Problem 11 :
Find the value of y :
(y2)2.5 = -32
Problem 12 :
h(x) = 2x
The function is h is defined above. What is h(5) - h(3)?
Problem 13 :
If 3x = 10, what is the value of 3x-3?
Problem 14 :
If x-1/3 = 5/2, then find the value of x.
Problem 15 :
If 5x/25y = 125, then solve for x in terms of y.
Problem 16 :
If a and b are positive even integers, which of the following is greatest ?
A) (-2a)b
B) (-2a)2b
C) (2a)b
D) 2a2b
Problem 17 :
If √(x√x) = xa, then find the value of a.
Problem 18 :
If x2 = y3 and x3z = y9, then find the value of z.
Problem 19 :
If n3 = x, n4 = 20x and n > 0, then find the value of n.
Problem 20 :
If x2y3 = 10 and x3y2 = 8, what is the value of x5y5?
Problem 21 :
If x8y7 = 333 and x7y6 = 3, what is the value of xy?
Problem 22 :
If 2x + 3 - 2x = k(2x), what is the value of k?
Problem 23 :
If xac ⋅ xbc = x30, x > 1 and a + b = 5, what is the value of c?
Problem 24 :
If (√9)-7 ⋅ (√3)-4 = 3k, then find the value of k.
Problem 25 :
In the equation 2√(x - 2) = 3√2, if x ≥ 2, then find the value of x.
Problem 26 :
x - 2 = √x
In the equation above x ≥ 0, find all the values of x which satisfy the equation.
1. Answer :
= 2m2 ⋅ 2m3
= (2 ⋅ 2)(m2 ⋅ m3)
= 4m2 + 3
= 4m5
2. Answer :
= m4 ⋅ 2m-3
= 2(m4 ⋅ m-3)
= 2m4 - 3
= 2m1
3. Answer :
= (4a3)2
= 42(a3)2
= 16a3 ⋅ 2
= 16a6
4. Answer :
= (x3)0
Anything to the zeroth power is equal to 1.
= 1
5. Answer :
6. Answer :
= (x2y-1)4
= (x2)4(y-1)4
= x8y-4
7. Answer :
= (3x)(2x1/2)
= 6x1 + 1/2
= 6x3/2
8. Answer :
9. Answer :
= (6ab2c3)(4b-2c-3d)
= 24ab2 - 2c3 - 3d
= 24ab0c0d
= 24a(1)(1)d
= 24ad
10. Answer :
= (x-ayb)3(x-3y-2)-a
= (x-a)3(yb)3(x-3)-a(y-2)-a
= x-3ay3bx3ay2a
= x-3a + 3ay3b + 2a
= x30y3b + 2a
= (1)y2a + 3b
= y2a + 3b
11. Answer :
(y2)2.5 = -32
y2 x 2.5= (-2)5
y5 = (-2)5
Since there is same exponent on both sides, bases can be equated.
y = -2
12. Answer :
h(x) = 2x
h(5) - h(3) :
= 25 - 23
= (2 ⋅ 2 ⋅ 2 ⋅ 2 ⋅ 2) - (2 ⋅ 2 ⋅ 2)
= 32 - 8
= 24
13. Answer :
3x-3 = 3x/33
= 3x/(3 ⋅ 3 ⋅ 3)
= 3x/27
Substitute 3x = 10.
= 10/27
14. Answer :
x-1/3 = 5/2
x = (5/2)-3/1
x = (5/2)-3
x = (2/5)3
Distribute the exponent to numerator and denominator.
x = 23 / 53
x = 8/125
15. Answer :
5x/25y = 125
5x/(52)y = 53
5x/52y = 53
5x - 2y = 53
Since there is same base on both sides, exponents can be equated.
x - 2y = 3
x = 2y + 3
16. Answer :
Because a and b are positive even integers, better we can assume some values for a and b and go through each choice.
Let a = 2 and b = 2.
Substitute a = 2 and b = 2 in each option.
A : [-2(2)]2 = (-4)2 = 16
B : [-2(2)]2(2) = (-4)4 = 256
C : [2(2)]2 = (4)2 = 16
D : 2(2)2(2) = 2(2)4 = 2(16) = 32
So, option B is the greatest.
17. Answer :
√(x√x) = xa
√(x ⋅ x1/2) = xa
√(x1 + 1/2) = xa
√(x3/2) = xa
(x3/2)1/2 = xa
x3/4 = xa
3/4 = a
18. Answer :
x3z = y9
x3z = y3(3)
x3z = (y3)3
Substitute x2 for y3.
x3z = (x2)3
x3z = x6
3z = 6
Divide each side by 3.
z = 2
19. Answer :
n4 = 20x
n3 ⋅ n = 20x
Substitute x for n3.
x ⋅ n = 20x
nx = 20x
Divide each side by x.
n = 20
20. Answer :
x2y3 = 10 ----(1)
x3y2 = 8 ----(2)
Multiply (1) and (2).
x2y3 ⋅ x3y2 = 10 ⋅ 8
x2+ 3y3 + 2 = 80
x5y5 = 80
21. Answer :
x8y7 = 333 ----(1)
x7y6 = 3 ----(2)
Divide (1) and (2).
(x8y7)/(x7y6) = 333/3
x8 - 7y7- 6 = 111
xy = 111
22. Answer :
2x + 3 - 2x = k(2x)
2x ⋅ 23 - 2x = k(2x)
Factor 2x on the left side.
2x(23 - 1) = k(2x)
Divide both sides by 2x.
23 - 1 = k
8 - 1 = k
7 = k
23. Answer :
xac ⋅ xbc = x30
xac + bc = x30
Since there is same base (x) on both sides, exponents can be equated.
ac + bc = 30
c(a + b) = 30
Substitute a + b = 5.
c(5) = 30
Divide both sides by 5.
c = 6
24. Answer :
(91/2)-7 ⋅ (31/2)-4 = 3k
(9)-7/2 ⋅ (3)-4/2 = 3k
(32)-7/2 ⋅ 3-2 = 3k
32 ⋅ (-7/2) ⋅ 3-2 = 3k
3-7 ⋅ 3-2 = 3k
3-7 - 2 = 3k
3-9 = 3k
k = -9
25. Answer :
2√(x - 2) = 3√2
Square both sides to get rid of the radicals.
[2√(x - 2)]2 = (3√2)2
22 ⋅ [√(x - 2)]2 = 32 ⋅ (√2)2
4 ⋅ (x - 2) = 9 ⋅ 2
4x - 8 = 18
Add 8 to each side.
4x = 26
Divide each side by 4.
x = 6.5
26. Answer :
x - 2 = √x
Square both sides to get rid of the square root on the right side.
(x - 2)2 = (√x)2
(x - 2)(x - 2) = x
x2 - 2x - 2x + 4 = x
x2 - 4x + 4 = x
Subtrtact x from both sides.
x2 - 5x + 4 = 0
Factor and solve.
x2 - 4x - x + 4 = 0
x(x - 4) - 1(x - 4) = 0
(x - 4)(x - 1) = 0
x - 4 = 0 or x - 1 = 0
x = 4 or x = 1
Verify the solutions with the original equation.
x = 4 : x - 2 = √x 4 - 2 = √4 2 = 2 ✔ |
x = 1 : x - 2 = √x 1 - 2 = √1 -1 = 1 ✘ |
x = 2 staisfies the original squation and x = 1 doesn't.
Therefore, the solution is x = 2.
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