Solve the following pairs of equations using the comparison method: (ii) 2x - 3y = 8 and (x+y)/(x-y) = 7/3. (v) x + y = 11 and y + 2 = (1/8)(10y + x).

Mathematics
Solve the following pairs of equations using the comparison method: (ii) 2x - 3y = 8 and (x+y)/(x-y) = 7/3. (v) x + y = 11 and y + 2 = (1/8)(10y + x).

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Answer

x=295, y=65x = \frac{29}{5},\ y = \frac{6}{5}

(ii)

{2x3y=8x+y=7\begin{cases} 2x - 3y = 8 \\ x + y = 7 \end{cases}

Step 1: Solve the second equation for xx.
x+y=7x + y = 7
x=7yx = 7 - y

Step 2: Substitute x=7yx = 7 - y into the first equation.
2(7y)3y=82(7 - y) - 3y = 8
142y3y=814 - 2y - 3y = 8
145y=814 - 5y = 8

Step 3: Solve for yy.
5y=814-5y = 8 - 14
5y=6-5y = -6
y=65=65y = \dfrac{-6}{-5} = \dfrac{6}{5}

Step 4: Substitute y=65y = \dfrac{6}{5} into x=7yx = 7 - y.
x=765=35565=295x = 7 - \dfrac{6}{5} = \dfrac{35}{5} - \dfrac{6}{5} = \dfrac{29}{5}

x=295x = \dfrac{29}{5}, y=65y = \dfrac{6}{5}
x = \frac{29{5},\ y = \frac{6}{5}}

(iii)

{x+y=7xy=3\begin{cases} x + y = 7 \\ x - y = 3 \end{cases}

Step 1: Add the two equations.
(x+y)+(xy)=7+3(x + y) + (x - y) = 7 + 3
2x=102x = 10
x=102=5x = \dfrac{10}{2} = 5

Step 2: Substitute x=5x = 5 into the first equation.
5+y=75 + y = 7
y=75=2y = 7 - 5 = 2

x=5x = 5, y=2y = 2
x = 5,\ y = 2

(iv)

{x+y=11y+2=10y+x8\begin{cases} x + y = 11 \\ y + 2 = \dfrac{10y + x}{8} \end{cases}

Step 1: Multiply the second equation by 8 to eliminate the denominator.
8(y+2)=10y+x8(y + 2) = 10y + x
8y+16=10y+x8y + 16 = 10y + x

Step 2: Solve for xx.
x=8y+1610yx = 8y + 16 - 10y
x=162yx = 16 - 2y

Step 3: Substitute x=162yx = 16 - 2y into the first equation.
(162y)+y=11(16 - 2y) + y = 11
16y=1116 - y = 11

Step 4: Solve for yy.
y=1116-y = 11 - 16
y=5-y = -5
y=5y = 5

Step 5: Substitute y=5y = 5 into x=162yx = 16 - 2y.
x=162(5)x = 16 - 2(5)
x=1610=6x = 16 - 10 = 6

x=6x = 6, y=5y = 5
x = 6,\ y = 5

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Quick Answer

(ii) 2x - 3y = 8 \\ x + y = 7 Step 1: Solve the second equation for x. x + y = 7 x = 7 - y Step 2: Substitute x = 7 - y into the first equation.

Solve the following pairs of equations using the comparison method: (ii) 2x - 3y = 8 and (x+y)/(x-y) = 7/3. (v) x + y = 11 and y + 2 = (1/8)(10y + x).
Mathematics

This mathematics problem involves applying core mathematical principles and formulas. Below you will find a complete step-by-step solution with detailed explanations for each step, helping you understand not just the answer but the method behind it.

ScanSolve AI Answer
(ii) 2x - 3y = 8 \\ x + y = 7 Step 1: Solve the second equation for x. x + y = 7 x = 7 - y Step 2: Substitute x = 7 - y into the first equation. 2(7 - y) - 3y = 8 14 - 2y - 3y = 8 14 - 5y = 8 Step 3: Solve for y. -5y = 8 - 14 -5y = -6 y = (-6)/(-5) = (6)/(5) Step 4: Substitute y = (6)/(5) into x = 7 - y. x = 7 - (6)/(5) = (35)/(5) - (6)/(5) = (29)/(5) x = (29)/(5), y = (6)/(5) x = (29)/(5),\ y = (6)/(5) (iii) x + y = 7 \\ x - y = 3 Step 1: Add the two equations. (x + y) + (x - y) = 7 + 3 2x = 10 x = (10)/(2) = 5 Step 2: Substitute x = 5 into the first equation. 5 + y = 7 y = 7 - 5 = 2 x = 5, y = 2 x = 5,\ y = 2 (iv) x + y = 11 \\ y + 2 = (10y + x)/(8) Step 1: Multiply the second equation by 8 to eliminate the denominator. 8(y + 2) = 10y + x 8y + 16 = 10y + x Step 2: Solve for x. x = 8y + 16 - 10y x = 16 - 2y Step 3: Substitute x = 16 - 2y into the first equation. (16 - 2y) + y = 11 16 - y = 11 Step 4: Solve for y. -y = 11 - 16 -y = -5 y = 5 Step 5: Substitute y = 5 into x = 16 - 2y. x = 16 - 2(5) x = 16 - 10 = 6 x = 6, y = 5 x = 6,\ y = 5