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10 votes
Simplify and please show working!
4x^2-25/2x^2-7x+5

User Didier L
by
4.8k points

1 Answer

6 votes

Answer:

-17x2 - 14x + 10

————————————————

2

Explanation:

STEP

1

:

25

Simplify ——

2

Equation at the end of step

1

:

25

(((4•(x2))-(——•x2))-7x)+5

2

STEP

2

:

Equation at the end of step 2

25x2

(((4 • (x2)) - ————) - 7x) + 5

2

STEP

3

:

Equation at the end of step

3

:

25x2

((22x2 - ————) - 7x) + 5

2

STEP

4

:

Rewriting the whole as an Equivalent Fraction

4.1 Subtracting a fraction from a whole

Rewrite the whole as a fraction using 2 as the denominator :

22x2 22x2 • 2

22x2 = ———— = ————————

1 2

Equivalent fraction : The fraction thus generated looks different but has the same value as the whole

Common denominator : The equivalent fraction and the other fraction involved in the calculation share the same denominator

Adding fractions that have a common denominator :

4.2 Adding up the two equivalent fractions

Add the two equivalent fractions which now have a common denominator

Combine the numerators together, put the sum or difference over the common denominator then reduce to lowest terms if possible:

22x2 • 2 - (25x2) -17x2

————————————————— = —————

2 2

Equation at the end of step

4

:

-17x2

(————— - 7x) + 5

2

STEP

5

:

Rewriting the whole as an Equivalent Fraction :

5.1 Subtracting a whole from a fraction

Rewrite the whole as a fraction using 2 as the denominator :

7x 7x • 2

7x = —— = ——————

1 2

Adding fractions that have a common denominator :

5.2 Adding up the two equivalent fractions

-17x2 - (7x • 2) -17x2 - 14x

———————————————— = ———————————

2 2

Equation at the end of step

5

:

(-17x2 - 14x)

————————————— + 5

2

STEP

6

:

Rewriting the whole as an Equivalent Fraction :

6.1 Adding a whole to a fraction

Rewrite the whole as a fraction using 2 as the denominator :

5 5 • 2

5 = — = —————

1 2

STEP

7

:

Pulling out like terms :

7.1 Pull out like factors :

-17x2 - 14x = -x • (17x + 14)

Adding fractions that have a common denominator :

7.2 Adding up the two equivalent fractions

-x • (17x+14) + 5 • 2 -17x2 - 14x + 10

————————————————————— = ————————————————

2 2

STEP

8

:

Pulling out like terms :

8.1 Pull out like factors :

-17x2 - 14x + 10 = -1 • (17x2 + 14x - 10)

Trying to factor by splitting the middle term

8.2 Factoring 17x2 + 14x - 10

The first term is, 17x2 its coefficient is 17 .

The middle term is, +14x its coefficient is 14 .

The last term, "the constant", is -10

Step-1 : Multiply the coefficient of the first term by the constant 17 • -10 = -170

Step-2 : Find two factors of -170 whose sum equals the coefficient of the middle term, which is 14 .

-170 + 1 = -169

-85 + 2 = -83

-34 + 5 = -29

-17 + 10 = -7

-10 + 17 = 7

-5 + 34 = 29

-2 + 85 = 83

-1 + 170 = 169

Observation : No two such factors can be found !!

Conclusion : Trinomial can not be factored

Final result :

-17x2 - 14x + 10

————————————————

2

User William Denton
by
4.4k points