Download Algebra 1 – 2.10

Algebra 1 – 2.10
Solve for the variable.
• 2m + 5 = 35
• 7j = 5j + 10
Solve these equations!
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6x + 2 = x + 10
3x = -15
2a + 5 = a + 8
11m + 1 = 8m + 28
These are the left sides of
equations. Write an expression for
the right side so that x=3 is a
soluation of the equation.
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2(x+1)
3x – 1
7x + 5 + 2(x – 1)
Any expression at all
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I picked a number.
I multiplied it by 2.
I added 3.
I subtracted 8.
I got 13.
I picked a number.
I multiplied by 5.
I added 6.
I got my starting
number times 3 plus
12.
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I picked a number.
I multiplied by 7.
I added 18.
My result was ten
times my starting
number.
I picked a number.
I added 1.
I multiplied by 6.
I added 1 again.
I got something 18
more than my starting
number.
2.11: the basic moves for
solving equations
SHORT CUT: because drawing
boxes gets kind of time consuming
Here are the basic moves:
1. Adding: you can add the same number to
each side without changing the solution.
2. You can multiply each side by the same
number (except zero!) without changing the
solution.
Extension of basic rules
1. Subtraction
2. Division
Practice:
• Use the basic moves to solve: 3s – 5 = s + 7
• Explain the moves you took at each step
• Solve: 4x + 3 = 7x + 15