Answer:
D.
Step-by-step explanation:
The formula is Sum(n) = (n -2) 180.
The digit in the tens place is 10 times bigger than the digit in the ones place
<span>1) 3x-2=x+10
</span><span>Now, lets solve this step-by-step.
</span><span>
3x - 2 = x + 10
-x -x
</span><span>
</span><span>3x - x = 2x 2x - 2 = 10
</span><span>
</span><span>2x - 2 = 10
</span>2x - 2+2 = 10+2 The inverse operation helps isolate the variable.
<span>
2x = 12
2x/2 = 12/2
x = 12/2
x = 6</span><span>
Answer: x = 6
2) x + 4 = 19 - 2x </span>
We can solve this much faster
x + 4 = 19 - 2x
+2x
x+2x = 3x
3x + 4 = 19
-4 -4
19-4 = 15
3x= 15
3x/3 = 15/3
x= 5
Answer: x = 5
3) <span>8x - 20 = x + 15
Much faster now!!
8x - 20 = x + 15
-x
8x-x = 7x
7x - 20 = 15
+20 +20
15+20 = 35
7x = 35
7x/7 = 35/7
x = 35/7
x = 5
Answer: x= 5</span>
Answer: a = 18
explanation:
2(a + 10) = 56 -> distribute the 2
2a + 20 = 56 -> subtract 20 from both sides
2a = 56 - 20
2a = 36 -> divide both sides by 2
a = 18
