Question

Solve the following simultaneous equations using an appropriate method.

a) 7x + 3y = 16
y = 4x - 1

b) 2x + y = 8
4x + 3y = 16

c) -3x + 2y = 19
4x + 5y = 13

d) -3x + 7y = 9
4x - 3y = 7

e) -4x + 5y = -7
x = 23 - 3y

f) y = -x
y = -2/5x - 1/5

Answer 1

a) x = 1 , y = 3

Explanation:

a) 7x + 3y = 16

y = 4x - 1

or

3y + 7x = 16 ... (i)

y - 4x = -1 ... (ii)

Solving the simultaneous equation by substitution;

Equation (ii) tells us that y = 4x - 1

Substituting that in (i) gives;

3(4x - 1) + 7x = 16

12x - 3 + 7x = 16

19x = 16 + 3 = 19

x =
`(19)/(19)` = 1

y = 4(1) - 1 = 3

Answer 2

Good evening ,

Look at the photo below for the answer.

:)