Hasil perhitungan dari akar pangkat dua 9×3+15×5 adalah

2. Carl needs 15 hours longer than Jennifer to paint a room. If they work together, they can complete the job in 4 hours. Explai

nasty-shy [4]

Answer:

Jennifer would complete the job on her own in 5 hours.

Step-by-step explanation:

Solving a quadratic equation:

Given a second order polynomial expressed by the following equation:

$ax^{2} + bx + c, a\neq0$ .

This polynomial has roots $x_{1}, x_{2}$ such that $ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})$ , given by the following formulas:

$x_{1} = \frac{-b + \sqrt{\Delta}}{2*a}$

$x_{2} = \frac{-b - \sqrt{\Delta}}{2*a}$

$\Delta = b^{2} - 4ac$

Rates

The together rate is the sum of their separates rate.

We have that:

Jennifer takes x hours to complete the job on her own, so her rate is 1/x.

Carl needs 15 hours longer than Jennifer, that is, 15 + x hours, so his rate is 1/(15+x).

The together rate is 1/4. So

$\frac{1}{4} = \frac{1}{x} + \frac{1}{15+x}$

$\frac{1}{4} = \frac{15 + x + x}{x(15+x)}$

$\frac{1}{4} = \frac{15 + 2x}{x(15+x)}$

Applying cross multiplication.

$x^2 + 15x = 4(15 + 2x)$

$x^2 + 15x = 60 + 8x$

$x^2 + 7x - 60 = 0$

Quadratic equation with $a = 1, b = 7, c = -60$ . So

$\Delta = 7^{2} - 4*1*60 = 289$

$x_{1} = \frac{-7 + \sqrt{289}}{2} = 5$

$x_{2} = \frac{-7 - \sqrt{289}}{2} = -12$

Since the time to complete the job has to be a positive value.

Jennifer would complete the job on her own in 5 hours.

4 0

3 years ago

"If < A and then m< A + m/B = 90°" A. Complement Theorem B. Definition of a Right Angle C. Congruent Complemen

9966 [12]

If < A and then m< A + m/B = 90°, then D. Definition of Complementary Angles

<h3>What is a complementary angle?</h3>

When the sum of two angles is 90°, the angles are said to be complementary. In other words, if two angles add up to form a right angle, they are called complementary angles. The two angles are said to complement each other in this context.

Supplementary angles are two angles that add up to 180 degrees, whereas complementary angles are two angles that add up to 90 degrees.

An angle measuring 72 degrees has a complement of 18 degrees.

Therefore, based on the information given, the correct option is D.

Learn more about complementary angles on:

brainly.com/question/16281260

#SPJ1

8 0

1 year ago

Which expression is equivalent to -4/7 - 8/9 + 4/7 - 9/8

olya-2409 [2.1K]

Answer:

I misunderstood the question before, but here are two expressions equivalent to -4/7 - 8/9 + 4/7 - 9/8.

71/72 + 70/72 +4/72

-1/7 - 3/7 - 5/9 - 3/9 + 2/7 +2/7 - 4/8 - 5/8

Solved: -2 1/72

Step-by-step explanation:

I could simply take the answer you get when combining all of the fractions, and I can make a new expression out of it. For example, I could use: 71/72+ 70/72+4/72. Or I could break apart all of the original fractions into smaller fractions. Example: -1/7 - 3/7 - 5/9 - 3/9 + 2/7 +2/7 - 4/8 - 5/8.

To solve: Start by combining -4/7 and 4/7 to make 0, shortening your equation. Then continue by making the fractions remaining, 8/9 and -9/8, have a common denominator. To do this, we multiply -8/9 by 8, and -9/8 by 9. Then, we have -64/72 and -81/72. Then, we can combine the numerators of the fractions, as they have common denominators, and we get the fraction -145/72. We can then simplify this to -2 1/72.

Hope this helps!

5 0

3 years ago

20 points -simplify fully

natulia [17]

Answer:

4√7

Step-by-step explanation:

5√7 + √7 - 2√7

Taking out common term, √7.

= √7 ( 5 + 1 - 2)

Simplify the terms in the bracket.

= √7 (4)

= 4 √7

7 0

3 years ago

Read 2 more answers

The temperature in Berlin is -7 °C and the temperature in Istanbul is -3 °C.

Orlov [11]

Answer:

(a) is 4*C and (B) is 16*C

5 0

2 years ago