Standard form, hmm.
Multiplying an exponent is just adding, so let us do this.
Simplified, the answer should be
The first equation is
The second equation is
If you sum the two equations you'll cancel y:
And since the sum must be 11, we have y=9.
The professional runner can run 4 1/6 miles in 30 minutes.
Since the professional can run 1 1/4 times as far in 30 minutes, we multiply 3 1/3 by 1 1/4:
(3 1/3)(1 1/4)
Convert each to an improper fraction (multiply the whole number by the denominator and add the numerator):
10/3(5/4) = 50/12 = 25/6 = 4 1/6.
Answer: girls=20, sister=10
Step-by-step explanation:
Let x = the girl's sister's age (present)
Let 2x= the girl's age (present)
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According to the question
(x+5)(2x+5)=375
Expand parentheses by FOIL (First Outer Inner Last)
2x²+5x+10x+25=375
Combine like term (5x and 10x)
2x²+15x+25=375
Subtract 375 on both sides
2x²+15x+25-375=375-375
2x²+15x-350=0
Find the factors (cross factor)
(x-10)(x+17.5)=0
x=10 or x=-17.5 (rej) ⇔ the age can't be negative
the girl's age is 20, and her sister's age is 10.
