If triangle DEF is an isosceles triangle with DE is congruent to EF, find x and the measure of each side

Step-by-step explanation:

Given that,

DE = 8x - 13

EF = 5x + 17

DF = x + 21

Also,

DE = EF

which means that,

8x - 13 = 5x + 17

8x - 5x = 17 + 13

3x = 30

x = 30/3

x = 10

Now,

DE = 8x - 13 = 8×10 - 13 = 80 - 13 = 67cm

EF = 5x + 17 = 5×10 + 17 = 50 + 17 = 67cm

DF = x + 21 = 10 + 21 = 31cm

3. (5x + 1) - (-10x + 6)

simplify the answer choice. combine like terms. remember to distribute the negative to the terms inside the second parenthesis. also remember that two negatives = one positive, and one of each sign = negative.

- (-10x + 6) = + 10x - 6

simplify. combine like terms:

5x + 1 + 10x - 6

5x + 10x + 1 - 6

15x - 5

∴ it is your answer

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answer:   c ?

step-by-step explanation: