Skills 3: Substitution with Variables
Qns 1-5: Evaluate the following expressions when S = 8 and T = 4
1)
2)
S + T = 8+4=
S–T=
12
3)
4)
𝐒
𝐓
5)
ST + S =
𝟖
= =𝟐
𝟒
2ST – T =
(2 x 8x 4)- 4=
Qns 6-10: Substitute the following values into the expressions and calculate the
answer: a = 3 b = 5 c = 8 d = 10
6)
7)
a+b=
8)
9)
d–c=
𝐝
𝐛
cd + ab =
(8x10) +(3 x
5)=80 +15 =
=
10)
3ad – 2bc =
Qns 11-15: Substitute the following values into the expressions and calculate the
answer: d = -2 e = 6 x = -4 y = 7
11)
e–y=
12)
2d – x =
13)
𝟑𝐞
𝐱𝐲
𝟏𝟖
−𝟐𝟖
=
𝟑𝐱𝟔
−𝟒𝐱 𝟕
−𝟏𝟖
=
=
𝟐𝟖
−𝟗
=
=
𝟏𝟒
14)
(2dx) + (de)
=
(2 x -2 x -4)
+(-2 x 6)=
16+-12 =
16 -12 = 4
15)
-3x – dy =
Extension
Qns 16-20: Rewrite the following table of values and fill it out, using the rule from
each question:
x
y
16)
y=x+4
3|Page
17)
-2
-1
18)
y = 3x
0
1
2
19)
y = 3x – 2
20)
y = -4x + 6
y=
4|Page
𝐱
𝟐