Question

Dannika solved this equation: -2(x + 4) = 10. Below are her steps. Step 1: −2 (x+4)=10 Step 2: −2(x) + −2(4) =10 Step 3: −2x +−8 =10 Step 4: −8 −8 Step 5: −2x =2 Step 6: ÷−2 ÷−2 Step 7: x=1 Analyze Dannika's work. Dannika made 2 mistakes.

Answer 1

x = -9

Explanation:

Given:

-2(x + 4) = 10.

Dannika's solution

-2(x + 4) = 10.

Step 1: −2 (x+4)=10

Step 2: −2(x) + −2(4) =10

Step 3: −2x +−8 =10

Step 4: −8 −8

Step 5: −2x =2

Step 6: ÷−2 ÷−2

Step 7: x=1

Correct calculation

-2(x + 4) = 10.

-2x - 8 = 10

Add 8 to both sides

-2x - 8 + 8 = 10 + 8

-2x = 18

Divide both sides by -2

x = 18 / -2

x = -9

Dannika made mistake in step 3 by saying + * - 8= +8 and step 4 by subtracting 8 from both sides of the equation