Answer:
Q 19) x = 4; y = 8.
Q 20) x = 0 ; y = 0.
Q 21) x = -1; y = -5.
Step-by-step explanation:
Q 19)
y = 3x - 4 (Equation 1)
x - 4y = -28 (Equation 2)
Put Equation 2 in Equation 1:
x - 4(3x - 4) = -28.
x - 12x + 16 = -28
-11x = -44.
x = -44/-11.
x = 4.
Put x = 4 in Equation 1:
y = 3(4) - 4.
y = 12 - 4.
y = 8.
Q 20)
2x - 3y = 13x - 4y (Equation 1)
-3x - 2y = 0 (Equation 2).
From Equation 2:
-2y = 3x.
y = -3x/2 (Equation 3).
Put Equation 3 in Equation 1:
2x - 3(-3x/2) = 13x - 4(-3x/2).
2x + 4.5x = 13x + 6x.
12.5x = 0.
x = 0.
Put x = 0 in Equation 3:
y = 0.
Q 21)
y = 4x - 1 (Equation 1).
y = -2x - 7 (Equation 2).
Since y = y, therefore:
4x - 1 = -2x - 7.
6x = -6.
x = -1.
Put x = -1 in Equation 1:
y = 4(-1) - 1.
y = -4 - 1.
y = -5.
In short:
Q 19) x = 4; y = 8!!!
Q 20) x = 0 ; y = 0!!!
Q 21) x = -1; y = -5!!!
Perpendicular lines have negative reciprocal slopes. So if the slope is -2/5...to find the negative reciprocal, " flip " the slope and change the sign.
So we flip -2/5 and we get 5/-2...and now we change the sign...and we get 5/2. So our perpendicular slope will be 5/2.
Answer: The expression represents the price of the skateboard when it is on sale for 25% off = 0.75p
Step-by-step explanation:
Given: Regular price of a skateboard is p.
Discount = 25% off = 0.25p
Now, the price of the skateboard when it is on sale for 25% off = p - Discount
= p -0.25p
= (1-0.25)p
= 0.75p
Hence, the expression represents the price of the skateboard when it is on sale for 25% off = 0.75p
where x is the estimated value and xr the real value
the percent error is 10.71%
Answer:
the answer is 4
Step-by-step explanation:
you divide -4 to both sides and 16 divided by -4 is 4