Answer:
C
Step-by-step explanation:
We can solve simultaneous equations using substitution method, elimination method or graphical method. But for this purpose, we will be using the elimination method.
3x+4y=8 Equation 1
2x+y=42 Equation 2
Multiply Equation 1 by 2 and equation 2 by 3, so as to get the same coefficient for x
2(3x+4y=8)= 6x+8y=16 Equation 3
3(2x+y=42)= 6x+3y=126 Equation 4
Subtract equation 4 from 3, to eliminate x
6x-6x=0
8y-3y= 5y
16-126= -110
We now have 5y=-110
Divide both sides by 5,
y= -110/5
= -22
Substituting for y in equation 2
2x+(-22)= 42
2x= 42+22
2x=64
x= 64/2
= 32
(x, y)
(32, -22)
Sub in 4 as x
3(4) - 29
= -17
Answer:
see explanation
Step-by-step explanation:
(a)
x² + 2x + 1 = 2x² - 2 ( subtract x² + 2x + 1 from both sides
0 = x² - 2x - 3 ← in standard form
0 = (x - 3)(x + 1) ← in factored form
Equate each factor to zero and solve for x
x + 1 = 0 ⇒ x = - 1
x - 3 = 0 ⇒ x = 3
-----------------------------------
(b)
-
=
( multiply through by 15 to clear the fractions )
5(x + 2) - 2 = 3(x - 2) ← distribute parenthesis on both sides
5x + 10 - 2 = 3x - 6
5x + 8 = 3x - 6 ( subtract 3x from both sides )
2x + 8 = - 6 ( subtract 8 from both sides )
2x = - 14 ( divide both sides by 2 )
x = - 7
--------------------------------------------
(c) Assuming lg means log then using the rules of logarithms
log
⇔ nlogx
log x = log y ⇒ x = y
Given
log(2x + 3) = 2logx
log(2x + 3) = log x² , so
x² = 2x + 3 ( subtract 2x + 3 from both sides )
x² - 2x - 3 = 0
(x - 3)(x + 1) = 0
x = 3 , x = - 1
x > 0 then x = 3
Answer:
(320 ÷ 50) × 100
Step-by-step explanation:
if you divide 320 by 50, you get what a single percent of the original price would be. So to get the original price, you just need 100 of the singular percentages, which you can get by taking a singular percentage (320 ÷ 50) and multipoint it by 100