CPM Homework Help : CCA Problem 3-21

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3-21.

Simplify and solve each equation below for $x$ . Record your work.

Hint:

Use the CPM algebra tiles application.

$3x−7=2$

Step 1(a):
Add $7$ to both sides.

$3x−7=2$
$\ \ \ \ +7\ +7$

$3x=9$
Step 2(a):
Divide both sides by $3$ .
$\frac{3x}{3}=\frac{9}{3}$
Answer (a):
$x=3$

$1+2x−x=x−5+x$

Step 1(b):
Combine like terms.
$x+1=2x−5$
Step 2(b):
Move $x$ to one side by subtracting $x$ from both sides.

$x+1=2x−5$
$−x\ \ \ −x$

$1=x−5$
Step 3(b):
Isolate $x$ by adding $5$ to both sides.

$x−5=1$
$+5\ \ \ \ +5$
Answer (b):
$x=6$

$3−2x=2x−5$

Hint (c):
Refer to parts (a) and (b).
Remember to check your work.

$3+2x−(x+1)=3x−6$

Hint (d):
Refer to parts (a) and (b).
Remember to check your work.

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