Respuesta :

Answer:

x = ± 5

Step-by-step explanation:

for the figure to be an isosceles trapezoid

then the lower base angles must be congruent , that is

3x² - 4 = 2x² + 21 ( subtract 2x² from both sides )

x² - 4 = 21 ( add 4 to both sides )

x² = 25 ( take square root of both sides )

x = ± [tex]\sqrt{25}[/tex] = ± 5

Nepalieducation

Answer:

x=5

Step-by-step explanation:

Here,

→[tex]2x^{2} +21=3x^{2} -4\\\\[/tex]

→[tex]21+4=3x^{2} -2x^{2} \\[/tex]

→[tex]x^{2} =25[/tex]

→[tex]x=\sqrt{25}[/tex]

→[tex]x=5[/tex]

Let's check whether they are equal or not by putting the value of x.

→[tex]2x^{2} +21[/tex]

→[tex](2*5^{2}) +21[/tex]

→[tex]50+21[/tex]

→[tex]71[/tex]

→[tex]3x^{2} -4[/tex]

→[tex](3*5^{2} )-4[/tex]

→[tex]75-4[/tex]

→71

Hence they are equal.

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