X representa o numero das suas respostas certas.
y represnta o numero das suas respostas erradas.
O total de perguntas <span>é 25, portanto
x + y = 25
Agora tratamos do dinheiro.
Come</span>ça com <span>R$ 500,00
Pelas x respostas certas, recebe 200x.
Pelas y respostas errads perde 150y.
O total de dineheiro inicial mais os ganhos menos as perdas s</span>ão iguais a
R$ 600,00, portanto
500 + 200x - 150y = 600
200x - 150y = 100
20x - 15y = 10
Temos um sistema de duas equações com duas variaveis.
<span>x + y = 25</span>
20x - 15y = 10
15x + 15y = 375
+ 20x - 15y = 10
---------------------------
35x = 385
x = 11
x + y = 25
11 + y = 25
y = 14
Resposta: Errou 14 perguntas.
Answer:
x = - 3 ± 
Step-by-step explanation:
Given
4x² + 24x = 4 ( divide through by 4 )
x² + 6x = 1
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(3)x + 9 = 1 + 9
(x + 3)² = 10 ( take the square root of both sides )
x + 3 = ± ( subtract 3 from both sides )
x = - 3 ±
Rainfall in July = 2.79 inches.
July has 31 days.
2.79 : 31 = x : 1 Set up the proportion
2.79 / 31 = x/1 Cross multiply and switch.
2.79*1 / 31 = x Do the division
0.09 inches = x Answer
Use a number line if you need 4/10 - 6/10 = -2/10a simpler way is to do the opposite 6/10 - 4/10 = 2/10 then the answer would be the opposite as well. so, -2/10
