Hello! I'm happy to help!
Question 13: First, we will need to find the value of x. We know that AB and BC are equal.
So, we can subtract x from both sides.
2x-8
-x
x-8
So, we get AB as x-8
x+17
-x
17
and BC as 17. We know that these are equal, so we need to find which x value will make them that way. In this case, x=25 because 25-8=17. We can now add back the x we removed earlier.
17+25=42
Therefore, both AB and BC have a value of 42. and AC will be the combined total.
42+42=84
So, for question 13, x=25, AB=42, BC=42, and AC=84.
Question 14: This question is similar, but we have an expression for AB and AC, instead of AB and BC. We still know that AB=BC, so we can also say that BC=x+6 also. To find x, we need to find a second expression that is equal to AC. We can ad AB and BC together to get that. (x+6)+(x+6)=2x+12. This expression is equal to the AC expression, so we can compare them to find x.
2x+12=3x-31
We need to single out the x on one side, by changing things in the same way on both sides.
2x+12=3x-31
-2x -2x
12=x-31
+31 +31
43=x
Now that we know our x value, we need to plug it in!
43+6=49
We now know that both AB and BC have a value of 49. Let's plug in the value for AC.
(43·3)-31
129-31
98
After plugging in the values, we know that AC is equal to 98. You could have also added AB and BC together, giving you 98 also.
To Summarize Question 14: x=43, AB=49, BC=49, AC=98.
Question 15: This one is very similar to the last, with a little more complexity to the expressions. First, let's simplify the expressions on AB and AC.
AB=3(3x-1) AB=9x-3
AC=5(2x+2) AC=10x+10
Now that we have the simplified expressions, let's solve. We need to find an equivalent expression for AC. We know that AB and BC are equivalent, and also add up to AC. We can copy the expression from AB to BC, and then add them
(9x-3)+(9x-3)=18x-6=AC
We now compare the two expressions in an equation to find x.
10x+10=18x-6
Again, we have to single out x on one side.
10x-10=18x-6
-10x -10x
10=8x-6
+6 +6
16=8x
This time, we need to divide both sides to single out x.
[tex]\frac{16}{8}[/tex]=[tex]\frac{8x}{8}[/tex]
2=x
Now that we have x, we need to plug it in to finish solving.
(9·2)-3
18-3
15
AB=15 BC=15
From here, you can do one of two things, add AB and BC together (easy), or plug in x for AC.
15+15=30 (10·2)+10
AC=30 20+10=30
AC=30
To Summarize Question 15: x=2, AB=15, BC=15, AC=30.
I'm always happy to help, keep learning! :D
