2x3 + 11x² + 20x+21 is divided by 2x7

Mathematics

1 answer:

svlad2 [7]3 years ago

6 0

Answer:

110.5

Step-by-step explanation:

i don't know if it's correct but I try to use the calculator.

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Algebra question.......

astraxan [27]

Answer:

Step-by-step explanation:

When you multiply 2 equations together, you just multiply them. You'd get x(3x-20) = 3x^2 - 20x, which is B

6 0

3 years ago

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2.<br>√3x + 7 + √x + 1 =2

taurus [48]

Answer:

x = -1

Step-by-step explanation:

The usual approach to these is to square the radicals until they are gone.

$\displaystyle\sqrt{3x+7}+\sqrt{x+1}=2\\\\(3x+7) +2\sqrt{(3x+7)(x+1)}+(x+1) = 4\qquad\text{square both sides}\\\\2\sqrt{(3x+7)(x+1)}=-4x-4\qquad\text{subtract $4x+8$}\\\\(3x+7)(x+1)=(-2x-2)^2\qquad\text{divide by 2, square again}\\\\3x^2+10x +7=4x^2+8x+4\qquad\text{simplify}\\\\x^2-2x-3=0\qquad\text{subtract the left expression}\\\\(x-3)(x+1)=0\qquad\text{factor}\\\\x=3,\ x=-1\qquad\text{solutions to the quadratic}$

Each time the equation is squared, the possibility of an extraneous root is introduced. Here, x=3 is extraneous: it does not satisfy the original equation.

The solution is x = -1.

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Using a graphing calculator to solve the original equation can avoid extraneous solutions. The attachment shows only the solution x = -1. Rather than use f(x) = 2, we have rewritten the equation to f(x)-2 = 0. The graphing calculator is really good at showing the function values at the x-intercepts.