If 2x + y = 7 and 3x - 2y = 3, by how much is 7x greater than 10?
1
3
7
10
17
Correct answer is C
2x + y = 7 = i
3x - 2y = 3 = ii
i x 2 + ii = 4x + 2y = 14
\(\frac {3x - 2y = 3}{7x = 17}\)
x = \(\frac {17}{7}\) = 7x = 17 x 1/7 x 7
17 - 10 = 7
Solve: 6(x - 4) + 3(x + 7) = 3
3/2
2/3
1/2
1/3
Correct answer is B
6(x - 4) + 3(x + 7) = 3
6x - 24 + 3x + 21 = 3
9x - 3 = 3
9x = 6
x = \(\frac{2}{3}\)
Find the equation whose roots are -2/3 and -1/4
12x2 + 11x + 2 = 0
12x2 - 11x + 2 = 0
x2 - 11/12x + 2 = 0
12x2 - 11x - 2 = 0
x2 - 11/12x - 2 = 0
Correct answer is A
x = \(-\frac{2}{3}\) and \(-\frac{1}{4}\)
\(\implies (x + \frac{2}{3}) = 0; (x + \frac{1}{4}) = 0\)
\((x + \frac{2}{3})(x + \frac{1}{4}) = 0\)
\(x^{2} + \frac{1}{4}x + \frac{2}{3}x + \frac{1}{6} = 0\)
\(x^2 + \frac{11}{12}x + \frac{1}{6} = 0\)
\(12x^2 + 11x + 2 = 0\)
2n2 - 2n
2n-2(1-2n)
2n + 22n + 2
22n
Correct answer is A
1/4(2n - 2n+2) = 2-2(2n - 2n x 22) = 2n x -2(1 - 22)= 22n-2
(20 - 22) = 22n-2 - 2n
Simplify \((\frac{3}{x} + \frac{15}{2y}) \div \frac{6}{xy}\)
\(\frac{2y - 5x}{4}\)
\(\frac{9(2x - 5x)}{x^2y^2}\)
\(\frac{5x - 2y}{2}\)
\(\frac{c^2y^2}{18y - 45x}\)
\(\frac{4}{2y - 5x}\)
Correct answer is A
\((\frac{3}{x} - \frac{15}{2y}) \div \frac{6}{xy}\)
= \((\frac{6y - 15x}{2xy}) \div \frac{6}{xy}\)
= \(\frac{6y - 15x}{2xy} \times \frac{xy}{6}\)
= \(\frac{3(2y - 5x)}{2xy} \times \frac{xy}{6}\)
= \(\frac{2y - 5x}{4}\)