Twice the sum of 15 and x as an algebraic expression
2 answers:
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Answer:
Step-by-step explanation:
and
and we are told that C is 6cm longer than A. That means that C = A + 6.
We are going to cross multiply each one of those ratios. The first one gives us
4A = 3B and the second one gives us
9B = 8C. But since C = A + 6, then
9B = 8(A + 6) and
9B = 8A + 48 and
Now we will solve the first equation above for A:
If 4A = 3B, then
and will use that as a sub for A in the second equation:
and
9B = 6B + 48 and
3B = 48 so
B = 16.
Now that we know B, we can use it to solve for A:
4A = 3(16) and
4A = 48 so
A = 12.
Then we can use that all the way back in the expression we set up for C:
C = A + 6 so
C = 12 + 6 so
C = 18
12 + 16 + 18 is the length of the string: 46cm