Question
(a) Find the value of 5x2 when x = –4.
Answer/Explanation
Ans: 80
(b) Make x the subject of the formula y = 5x2.
Answer/Explanation
Ans: \([\pm ]\sqrt{\frac{y}{5}}or\frac{\sqrt{y}}{\sqrt{5}}\)
Final answer
Question
(a) Solve the equation.
4x + 3 = 11
x = …………………………………………
(b) Make x the subject of the formula \(y = 4x^2 – 2\).
x = …………………………………………
Answer/Explanation
Ans:
(a) 2
(b) [x=] \(\sqrt{\frac{y+2}{4}}\) or \(\sqrt{(y+2)/4}\)
or \(\sqrt{\frac{y+2}{2}}\) oe final answer
Question
The diagram shows the graph of \(y = (x + 1)^2 for −4 \leq x\leq 2\)
(a) On the same grid, draw the line y = 3
(b) Use your graph to find the solutions of \((x + 1)^2= 3
Give each solution correct to 1 decimal place.
Answer/Explanation
(a)
(b) \(x^2+1+2x=3\)
\(x^2+2x-2=0\)
\(D=2^2-4(1)(-2)=12\)
\(\alpha,\beta=\frac{-2\pm\sqrt{12}}{2.1}\)
\(frac{-2+3.46}{2},\(frac{-2-3.46}{2}\)
=0.73,-2,73