Directed Numbers
The value of (-3)2
9
The point (a, 0) lies on the line 2x - 3y = 1.
The value of a is
0.5 or 1/2
40% of 200 =
80
A figure with 6 sides
Hexagon
The value of 1 - (-42)
17
The y-intercept of the line 3x + 2y = -18 is
-9
10% of a set are left-handed.
If 2 students are left-handed, the number of students in the set is
20
(-2a3b4)3
-8a9b12
Any two alternate angles are equal.
True or False?
False, because the two lines may not be parallel
The value of (-62) / (-3)2
-4
To solve 2x + y = 5 and 3x - 7y = 9 simultaneously, it is better to make y the subject. The reason is
no denominator will result when we write y = 5 - 2x
or
the coefficient of y in the first equation is 1
The weight of Sue reduces from 64 kg to 56 kg.
The percentage change is
-12.5%
Subtract the sum of a and b from the product of
(-2a + 1) and b
-2ab - a
In a triangle, the angles are a, a and 4a.
What kind of triangle is it?
Isosceles obtuse-angled triangle
The value of [(-9)-(-8)]2018
1
Consider the simultaneous equations
2x + 3y = 10
-3x - 3y = 9
The value of x is
-19
If a concert ticket is sold at a profit of 10%, the profit is 25. The selling price is
$275
Solve 4x - 3(x + 7) = 2(x+1).
-23
10 cubes of side 4 cm is melted and recast to become a trapezoidal prism with base area 32 cm2.
The height of the prism is
20 cm
(-9)^2/(-6^2)-(-0.5)(+0.5)
-2
Solve the simultaneous equations for a and b.
5/a+2/b=1
5/a - 7/b = 4
a=3 and b = -3
The processing time a e-Channel decreases from 12 seconds to 8 seconds. What is the percentage change?
-33 1/3%
Simplify (2x - 3y)2 - 4x(x + y).
9y2 -16xy
Point A(-2, 2) is rotated 90 degrees anti-clockwise about the origin to become point B. Point B is reflected along the y-axis to become point C.
The area of triangle ABC is
8 square units
(-4)(+2)(-1)/[(-4)-(+2)+(-1)]
-8/7
Suggest two linear equations in x and y such that the common solution is x = -2 and y = 1.
e.g. x+y=-1 and 3x-y=-7
If a souvenir is sold for $135 at 10% off, a profit of 35% will be made. The cost price of the souvenir is
$100
Comment on (3a-2b)^2 =3a^2-2b^2
It is incorrect. The answer should be
9a^2-12ab+4b^2
(3a-2b)^2 = (3a-2b)(3a-2b)=9a^2-6ab-6ab+4b^2
Each side of a rectangle is enlarged by a scale factor of 3.
Its new area is greater than the original area by ___ times.
9-1=8