Big Idea Math Algebra

Which step can solve the equation: -5x = 100

• add 5 to both sides of the equal sign

• multiply both sides of the equal sign by -5

• divide both sides of the equal sign by -5

• subtract -5 from both sides of the equal sign

solve the equation and state how many solutions it has:

3(5x + 2) = 15x

• 1 solution

• 2 solutions

• infinitely many solutions

• no solution

Simplify each equation. Tell whether the equation has one, no, or infinite solutions.

3x - 7 = 3(x - 3) + 2

• one

• no solutions

• infinite solutions

Simplify each equation. Tell whether the equation has one, no, or infinite solutions.

3x - 8 = 3(x - 4) + 1

• one

• no solutions

• infinite solutions

• x=25

• x=45

• x=1.8

• x=33

The current value of a rare coin is 70 times its original value, v (in dollars). The coin is worth $43. Write an equation to find the original value of the coin.

• 70 + v = 43

• 70v=43

• 43v=70

• 43 +v = 70

Translate: 
Four times a number plus six is 30.

• 4 + 6 = 30
• 4x + 6 = 30
• x + 4 times 6 = 30
• 30 = 4x

Find the error in the problem below
19 - 2k = 3k - 1
     +3k   +3k
19 + 1k = -1
-19           -19
k = -20

• They should have divided by 1 for the last step
• They should add 19 instead of subtracting 19
• I can not find an error
• Instead of adding 3k they should subtract 3k

• x=  9   1/3
• x = 21/4
• x = 5    1/4
• None of the above

• 7
• -16
• 4
• -15