Erica solved the equation −5x − 25 = 78; her work is shown below. Identify the error and where it was made. −5x − 25 = 78

2 answers:

7 0

Answer:

Step-by-step explanation:

she should have added 25 to both

3 0

Answer:

Step-by-step explanation:

She should have added 25 to each side in order to cancel it out.

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Temka [501]

$- x + 1 = 4x - 14 \\ - x - 4x = - 14 - 1 \\ - 5x = - 15 \\ x = 3$

Substitute x = 3 in any given equations. I will do in y = - x + 1

$y = - x + 1 \\ y = - 3 + 1 \\ y = - 2$

Therefore the answer is (3,-2)

7 0

3 years ago

Sveta_85 [38]

Your answer would be -2.2

8 0

3 years ago

zzz [600]

Answer:

B) 4√2

General Formulas and Concepts:

Calculus

Differentiation

Basic Power Rule:

Parametric Differentiation

Integration

Arc Length Formula [Parametric]: $\displaystyle AL = \int\limits^b_a {\sqrt{[x'(t)]^2 + [y(t)]^2}} \, dx$

Step-by-step explanation:

Step 1: Define

Identify

$\displaystyle \left \{ {{x = t - cos(t)} \atop {y = 1 - sin(t)}} \right.$

Interval [0, π]

Step 2: Find Arc Length

[Parametrics] Differentiate [Basic Power Rule, Trig Differentiation]: $\displaystyle \left \{ {{x' = 1 + sin(t)} \atop {y' = -cos(t)}} \right.$
Substitute in variables [Arc Length Formula - Parametric]: $\displaystyle AL = \int\limits^{\pi}_0 {\sqrt{[1 + sin(t)]^2 + [-cos(t)]^2}} \, dx$
[Integrand] Simplify: $\displaystyle AL = \int\limits^{\pi}_0 {\sqrt{2[sin(x) + 1]} \, dx$
[Integral] Evaluate: $\displaystyle AL = \int\limits^{\pi}_0 {\sqrt{2[sin(x) + 1]} \, dx = 4\sqrt{2}$