Question

Can someone please help answer this question on simultaneous equations?

Answer 1

1 knife cost £6.6

Explanation:

Simultaneous equation is;

4x = y ----------(equation 1)

12y + 16x = 105.64 ----------- (equation 2)

Rewrite equations:

4x=y;16x+12y=105.64

Step: Solve4x=yfor y:

4x=y

4x+−y=y+−y(Add -y to both sides)

4x−y=0

4x−y+−4x=0+−4x(Add -4x to both sides)

−y=−4x

−y/−1 = −4x/−1

(Divide both sides by -1)

y=4x

Step: Substitute 4x for y in 16x+12y=105.64:

16x+12y=105.64

16x+124x=105.64

64x=105.64(Simplify both sides of the equation)

64x/64 = 105.64/64

(Divide both sides by 64)

x=1.650625

Step: Substitute 1.650625 for x in y=4x:

y=4x

y=(4)(1.650625)

y=6.6025(Simplify both sides of the equation)

1 knife cost = 4x = 4(1.65) = 6.6

∴ 1 knife cost £6.6