Algebra 1
Unit 1
Day 9
Notes
One- and
Two-Step Equations
Name:________________________
Date:___________
Warm-Up:
If possible, find the number(s) that can REPLACE x in each of the following equations to make it TRUE.
a) x + 5 = 100
b) 5x = 100
c) x 2  25
d) 12 – x = 3
e)
12
3
x
f)
x
3
12
g)
x  2x
h)
3x  21
Notes:
a)
What is the opposite of multiplying x by 5?
5x
to undo you should:
b) What is the opposite of adding 3 to x?
3+ x
to undo you should:
c)
x–2
to undo you should:
x
4
to undo you should:
What is the opposite of subtracting 2 from x?
d) What is the opposite of dividing x by 4?
Examples –
1. Determine what the OPPOSITE/INVERSE operation is and solve the equation using algebra.
Show your work.
a) x + 7 = 10
b) x – 8 = 20
c) 5x = 30
d)
x
6
4
REVERSE PEMDAS = SADMEP
When solving equations you reverse the order of PEMDAS!
Undo the operations that are not attached to the variable 1st!
Solve each of the following equations for the variable.
a)
4 x 1  19
c) 3x + 11= 5
b)
x
 2  10
4
d)
3  2x  5
Block:______
Find the value of x in the following equations.
1) 2𝑥 + 9 = 7
2) 4𝑥 + 3 = 28
3) 2𝑥 − 0.6 = 4.8
4) 4 − 3𝑥 = −37
5) 21 = 9 − 3𝑎
6) 3𝑛 + =
7) – 𝑥 + 7 = −5
8) 10 − 𝑥 = 15
.
2
1
7
5
5
9) 8𝑐 − = 1
10) 4 − 5ℎ = 9
11) 13 = 3𝑥 − 2
12) 8 − 5𝑥 = −4
3