There are many ways to solve simultaneous linear equations. One of my favorite for finding integer solutions is graphing. The attached graph shows the solution to be ...
... (x, y) = (4, 7)
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You can also use Cramer's Rule, or the Vedic math variation of it, which tells you the solution to

is given by

Here, that means
... x = (9·67-5·75)/(9·8-5·3) = 228/57 = 4
... y = (75·8-67·3)/57 = 399/57 = 7
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A (graphing) calculator greatly facilitates either of these approaches.
Any of the tens i think (10=60, 20+50, etc.), but i am not too sure what is implied by regrouping. if i am right in thinking this only means "carrying" a digit after adding, then anything that adds up to 70 would work unless the sum of the digits in the ones place exceeded 9.
Answer:

Step-by-step explanation:

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<h3>
Answer:</h3>
3 11/15 cm
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Step-by-step explanation:</h3>
AE is the angle bisector of ∠A, so divides the sides of the triangle into a proportion:
... BE:CE = BA:CA = 7:8
Then ...
... BE:BC = 7 : (7+8) = 7:15
ΔDBE ~ ΔABC, so DE = 7/15 × AC
... DE = 7/15 × 8 cm = (56/15) cm
... DE = 3 11/15 cm
I have a picture of the work for it but I don’t know how to upload it I can put a file maybe!