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Solve the simultaneous equations 3x + 2y = -7 and x=4y+21

Substitute in the second equation into the first to eliminate x from the first equation. Solve for y which should, when solved (shown below), equal -5. Sub -5 back into either equation in the place of y to t...
JG
Answered by Jamie G. • Maths tutor
3909 Views

Matt has 3 piles of coins, A , B and C. Altogether there was 72p. Pile B had twice as much as pile A. Pile C had three times as much as pile B. How much money was in Pile C?

so we know that A+B+C= 72. We also know that B=2A (1) and C=3B which means C=6A (2) and with this information we can re arrange to equation to be only have one variable. so A+2A+6A= 72 Collecting all the ter...
ND
Answered by Nazli D. • Maths tutor
4070 Views

The new reading for James' electricity bill is 7580, and the old reading is 7510, the price per unit is 13p, how much does James have to pay for his electricity?

This question is tricky/unfair because you need to understand how meters work. The old reading was the last time the electricity bill was paid for, so the first thing you need to do is 7580-7510= 70. So that...
MZ
Answered by Michal Z. • Maths tutor
3315 Views

Solve simultaneously 2x + 3y = 18 and y = 3x – 5 to find the value of x and y.

sub the y value into the first eqn 2x + 3(3x-5) = 18 expand the brackets 2x +9x-15 = 18 add up the x values 11x -15 = 18 add 15 to both sides to cancel it out on the l.h.s 11x = 33 divide by 11 to get value ...
JG
Answered by Jessica G. • Maths tutor
4172 Views

Work out the gradient of the tangent to the curve (y=x^2-x-2) at the point where x=2

y=x^2-x-2y=(x+1)(x-2)The gradient (dy/dx) measures the rate of the change in y with respect to x. So this can be used to help us find the gradient of a function at any point along it. The question asks the t...
OG
Answered by Oriane G. • Maths tutor
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