Matemática, perguntado por rosaantunes204, 10 meses atrás

Encontre o zero das funções:

1) f(x)= -2x+5

2) f(x)= 2x-17

3) f(x)= -3x-15​

Soluções para a tarefa

Respondido por Usuário anônimo
0

1) f(x)= -2x+5

f(x) = 0\\-2x+5 = 0\\-2x = -5\\x = \frac{-5}{-2}\\x = \frac{5}{2}

2) f(x)= 2x-17

f(x) = 0\\2x-17 = 0\\2x = 17\\x = \frac{17}{2}\\

3) f(x)= -3x-15​

f(x) = 0\\-3x-15 = 0\\-3x = 15\\x = \frac{15}{-3}\\x = -5

Respondido por hkarlison
0

Explicação passo-a-passo:

Questão 1:

f(x) =  - 2x =  - 5 \\ - 2x = - 5 \: <strong> </strong><strong>*</strong><strong>( - 1)</strong><strong>\</strong><strong>:</strong> Como\: o\:valor\:de\:X \:é\:negativo,\\ vamos\:multiplicar \:por \:-1 \\  2x =  5  \\  x =  \frac{5}{ 2}

Prova:

Substituir\:o\:X\:por\:\frac{5}{ 2}

f(</strong><strong>\frac{5}{2}</strong><strong>) =  - 2</strong><strong>(</strong><strong>\frac{5}{ 2}</strong><strong> </strong><strong>)</strong><strong> </strong><strong>+</strong><strong> </strong><strong>5</strong><strong>\</strong><strong>:</strong><strong> </strong><strong> </strong><strong>\\ </strong><strong>-</strong><strong>5</strong><strong> </strong><strong>+</strong><strong> </strong><strong>5 </strong><strong>=</strong><strong> </strong><strong>0</strong><strong> </strong><strong>

Questão 2:

f(x) =  2x =  </strong><strong>1</strong><strong>7</strong><strong> </strong><strong>\</strong><strong>\</strong><strong>x =  \frac{</strong><strong>1</strong><strong>7</strong><strong>}{ 2}

Prova:

Substituir\:o\:X\:por\:\frac{</strong><strong>1</strong><strong>7</strong><strong>}{ </strong><strong>2</strong><strong>}

f(\frac{</strong><strong>1</strong><strong>7</strong><strong>}{2}) =  2(\frac{</strong><strong>1</strong><strong>7</strong><strong>}{ 2} ) </strong><strong>-</strong><strong> </strong><strong>1</strong><strong>7</strong><strong> \\ </strong><strong>1</strong><strong>7</strong><strong> </strong><strong>-</strong><strong> </strong><strong>1</strong><strong>7</strong><strong> = 0

Questão 3:

f(x) =  - </strong><strong>3</strong><strong>x =  </strong><strong>1</strong><strong>5 \\ - </strong><strong>3</strong><strong>x = </strong><strong>1</strong><strong>5 \:  *( - 1)\: Como\: o\:valor\:de\:X \:é\:negativo,\\ vamos\:multiplicar \:por \:-1 \\  </strong><strong>3</strong><strong>x =  </strong><strong>-</strong><strong> </strong><strong>1</strong><strong>5  \\  x =  \frac{</strong><strong>-</strong><strong> </strong><strong>1</strong><strong>5}{ </strong><strong>3</strong><strong>}</strong><strong> \\  x =  </strong><strong>-</strong><strong> </strong><strong>5</strong><strong>

Prova:

Substituir\:o\:X\:por\:</strong><strong>-</strong><strong> </strong><strong>5</strong><strong>

f(</strong><strong>5</strong><strong>) =  - </strong><strong>3</strong><strong>(</strong><strong>-</strong><strong>5</strong><strong> ) </strong><strong>-</strong><strong> </strong><strong>1</strong><strong>5\:  \\ </strong><strong>1</strong><strong>5 </strong><strong>-</strong><strong> </strong><strong>1</strong><strong>5 = 0

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