Math

420

Ppraew💗

Junior High 1年生

Substitution✨

2026.07.06 公開

コメントはまだありません。

ノートテキスト

ページ1:

Substitution in Expressions.
(a) a+b
(b) a-3
(C) 30
(d) 50-2
(e) 9/5
Given that a = 5
Find the values of:
,
=
5+6
= 11
=
5-3
= 2
JI
3x5
= 15
=
5(5)-2
=
23
IJ
=
5/5
= 1
52
=25
=
=
3(5)-1
=
14
52 + 10
=35
=
10-5
= 5
=50-52
=25
(f) 92
(g) 30-1
(h) a²+10
(i) 10-a
(j) 50-92
Given that
(a) a+b
(b) c-b
=
=
12
5
=
a = 10,b=2 and C-7, find the value of
(c) 2C+b=2(7)+2
=
16
(i) a²/20 = 10/20 = 5
) ath
a+b
3
=
= 4
3
(d) a+b-c
=
(e) 5+36
=
(f) 100-40
(g) a+b²
10+2-7= 5
=
5 + 3 (2) 11
=
100-4(10) = 60
2
=
10 + 2 -
1
14
(h) a²+2b = 10²+2(2) = 104

ページ2:

Given that
a=8,b=-3 and c=4,
creat an expression that will give a value of:
=(-Axb)-(C+2) = [(-8)* (-3)] - (4+2) = 18
(a) 20
(b) 18
(C) 25
=
2(a) + C
=
2(8) + 4 = 20
=
30+1
(d) 16
=
C²
=
3(8) +1
=25
42
=
16
(e) 28 = (ac) - [ b + (-1)] = (8×4)-(+) = 28
(f) -4
=
6+(-1)
= (-3) + (-1) = -4
Calculator Allowed
จ a = 2b+3c
Find the value of a when b-5 and C=2
a = 2(5)+3(2)
= 16
d = 5e-2f
Find the value of d
when e-4 and f= 6
d = 5(4) - 2 (6)
= 8

ページ3:

Substitution
Make x the subject of the equation
(a) F = x²- 3
F+3 = x²
× = √F+3
x² =
= F +3
Step 1: Move the constant
Add 3 to both side to get rid of -3
F +3 = X
Step2: Remove the square
Sine X is squared, take the square root of both sides.
X = ± √√F+3
I use ± (plus or minus) because both a positive and a
negative number have the same square.
For ex. 3² = 9
(-37209
So if x²-9, than x = ±3.
Final answer
X= ± √F+3
*Make x the subject
Rearrange the equation so that
X is alone.

ページ4:

(b) 3x-4 = 4
3× =
4+4
4+4
3
Step 1: Remove -4
To cancel the -4, add 4 to both sides.
3X-4+4
=
4+4
This simplifies to:
Step 2: Remove 3
3X mean 3xx.
3x = 4+4
To get just x, divide both side by 3.
ง
3X
=
4+4
So:
X = Y +4
3
3
3
Final answer
X = X +4
3

ページ5:

(c) m = 3n+ 2X
m-3n = 2X
m-3n
2
Step 1: Move 3h to the other side
Subtract 3n from both side:
m-3n = 2x
Step 2: Remove the 2
Divide both sides by 2:
m-3n
=
Final answer
X =
m-3n
2

ページ6:

(d) 4x + C = W
4X+C
4X = W-C
= W-C
4
Step Move c to the other side
1:
Subtract c from both side:
4x
=
W-C
Step 2: Remove the 4
Divide both side by 4:
✗
=
W-C
4
final answer
X = W-C
4

ページ7:

(e) dx-t=8
dx=8+t
>
=8+t
d
(f) 5 = x² - 3
S+3 = x²
√5+3
Step 1: Move + to the other side Step: Move -3 to the othe
Add to both sides:
dx = 8+t
Step2: Remove d
Since dxx = dx,
divide both sides by di
x = 8+t
final answer
X = 8+t
Side
Add 3 to both sides:
2
S+ 3 = x²
Step 2: Remove the square
Take the square root of both
Sides:
+
X = ± √5+3
final answer
ณ คณิต
d
X = ± √5+3

ページ8:

(9) 5CX
b
5CX = ab
=
ab
50
=
= a
(h) v² = u²+zax
√²-U² = 2ax
> = V²=U²
2d
Step 1: Remove the denominator Step 1: Move u² to the other
Multiply both sides by b:
Side
5cx = ab
Subtract u² from both sides:
Step 2: Remove Sc
√²-4² =
= 20x
Divide both sides by SC: Step2: Remove za
X = ab
5C
final answer
X = ab
50
Divide both side by za:
X = √² 4²
-
29
final answer
X = V² u²
V²u²
2a

ページ9:

(I) 3
3√
= W
=
x = kw³
Step 1: Remove the cube root
Cube both sides:
X
k
Step 2: Remove k
=
W³
Multiply both side by k:
X
=
kw 3
Final answer
X = kw³
จบ คณิดา