Answer:
Step-by-step explanation:
31) Multiply the entire equation by the LCM of 5 & 4 which is 20
[tex]20*\dfrac{2x^{2}}{5}+20*\dfrac{5x}{4}=10*20\\\\4*2x^{2}+5*5x = 200\\\\8x^{2}+25x - 200 = 0[/tex]
B
32) D
By trial & error method 17 * 15 = 255
33) x = 2
y = 4x² + 1
= 4*2² + 1 = 4*4 + 1
= 16 + 1
y = 17
B
34) D) all real numbers
35) Domain = all real numbers,
x = -2 ; y = -(-2+2)² - 7 = 0 - 7 = - 7
x = 0 ; y = -(0+2)² - 7 = -4 - 7 = -11
x = 4; y = -(4+2)² - 7 = - 6² -7 = -16 - 7 = - 23
C) y ≤ -7
36) t = 1 second
y = 160t - 40t² = 160*1 - 40*1² = 160 - 40
y = 120 m
C
37) Let the number be 'x'
x² + x = 165
x² + 4x - 165 = 0
Sum = 4
Product = -165
Factors = 15 , -11 {15*(-11) = -165 & 15+ (-11) = 4}
x² + 15x - 11x - 165 = 0
x(x + 15) - 11(x + 15)=0
(x + 15)(x - 11) = 0
x + 15 = 0 ; x - 11 = 0
x = -15 ; x = 11
C
38) y = 3(x + 1)² - 2
Plugin x = -1 ; y = 3(-1 +1)² - 2 = 0 - 2
y = -2
(-1 , -2)
D
39) y = 3(x - 9)² + 3
Plugin x = 9 ; y = 3(9-9) + 3 = 0 + 3 = 3
B
