3
2
1
-1
Correct answer is B
x + y = 2y - x + 1 = 5
x + y = 2y - x + 1
x + x + y - 2y = 1
2x - y = 1....(i)
2y - x + 1 = 5
-x + 2y = 5 + 1
-x = 2y = 4
x - 2y = -4 .....(ii)
solve simultaneously (i) x 2x - y = 1
(ii) x x - 2y = -4
2x - y = 1
=2x - 4y = -8
3y = 9
y = \(\frac{9}{3}\)
y = 3
substitute y = 3 into equation (i)
2x - y = 1
2x - 3 = 1
2x = 1 + 3
2x = 4
x = \(\frac{4}{2}\)
= 2
3% of a family's income is spent on electricity, 59% on food, 20% on transport, 11% on education...
Find the value of x in the figure above ...
If 3p = 4q and 9p = 8q - 12, find the value of pq. ...
sinθ = 1/2 and cosθ = -√3/2, what is the value of θ? ...
Solve the simultaneous equations y = 3x; 4y - 5x =14 ...
In a triangle PQT, QR = \(\sqrt{3}cm\), PR = 3cm, PQ = \(2\sqrt{3}\)cm and PQR = 30°. Find angle...
Evaluate \(\frac{12.02 \times 20.06}{26.04 \times 60.06}\), correct to three significant figures....